This material has been created through a cooperative effort of the Automated Vehicular Gate Systems Coalition. This group is supported by:
American Fence Association (AFA)
Door & Access Systems Manufacturers Association (DASMA) International Door Association (IDA)
National Ornamental and Miscellaneous Metals Association (NOMMA)
All Rights Reserved
4th Edition, Revision 3. October 2021.
Copyright 2020. American Fence Association
Introduction to Certified Gate Automation Designer
Gate Automation System Designer
Introduction to ASTM F2200 and MUTCD
Glossary and Common Terminology
Introduction to Certified Gate Automation Designer
Designing an automated gate system can be a lengthy and detailed process. It involves so much more than just putting together an equipment list. While every job or project is different, there are some factors that apply to every gate system.
There are other factors that will be specific to each project. The CGAD course was developed to help system designers gain an understanding on the factors that need to be considered when designing an automated gate system.
Automated gate systems are now being scrutinized by code enforcement officials and fire marshals across the country. The International Building Code, International Residential Code, and International Fire Code each address the current UL325 and ASTM F2200 standards and officials are making compliance to them a part of their inspection process.
The state of Nevada has for years mandated compliance with UL325 and Louisiana now requires any company that installs, or services Automated Gate Systems be licensed to operate in the state. Some states require a license (Burglar, Fire Alarm, etc.) to terminate any entry control system that has the capability to record data or monitor the activity.
It is imperative to know and understand the local and state requirements to design, install and service automated gate systems.
Before starting the system design, it is recommended that the local Code Enforcement and Fire Marshall offices be contacted for the local requirements. These requirements could be the size of the gate opening, setback from the public right of way, types of acceptable responder access devices, turn-a-rounds for denied access, etc.
As an industry professional, it is the system designer’s responsibility to know what is required and design the project accordingly.
Automated gate systems in their very nature cause traffic problems. Limiting access to a site means that traffic flow will be restricted at worst or greatly slowed from the normal pace that drivers are used to.
Great care must be given when designing a system to address these issues and negate their impact. A well-designed system that considers the system users, vehicle types, number of cycles per day, space restrictions and in general the type of access devices used will outlast a poorly designed system every time.
As the demographics of our population change, so must the systems we design and install. Walkers and bikers are on the rise as society moves to a greener mindset so their access and egress needs must be addressed. The over-65 segment of society is larger than ever before and as their reflexes slow and depth perception diminishes, placement of access equipment with room to maneuver should be considered.
Drivers have more distractions than ever before, and the system designer must consider this when designing a system. The melting pot is ever growing; bilingual signage is more prevalent today than any time in our history. The system designer should consider all the issues, uses, and circumstances the site will require to accommodate vehicular and pedestrian access safety adequately.
A key part of system design is taking into consideration why a property owner is putting in a gate system. They did not just wake up one day and say, “I think I will have a gate system installed.”
There is a reason for the decision to add an automated gate system. It is a system designer’s responsibility to determine what that reason is. If the system does not address this primary need of the customer, they may never be completely satisfied.
The system may function properly, but there will be something “missing” that the customer may not even be able to define. Something that makes them feel unfulfilled in how the system works or looks.
The reasons people add a gate system to their property can vary significantly, and it sometimes is difficult to define. It takes some investigation, and clear conversations with the customer to fill in these blanks. Ask these, and more, questions when visiting with the customer:
· What do they hope to get from the finished system?
· Remember “Expectations” are different from “Needs”.
· Did some events occur that caused them to put in a gate system?
· Kids playing and kicking a ball into the street.
· Dogs terrorizing the neighborhood.
· Are they trying to improve the aesthetic value of the property?
· Did a neighboring property add a gate, and they want to keep up?
· Are they addressing a security issue?
· Is this the contractor, putting in as economical of a gate as he can to meet the property requirements for a gate? (If so, allow for future expansion of the system once the property owner takes over).
· Determining how the customer expects the system to work, and what they are looking for will help with the system design. If the system does not meet these needs and expectations, the customer will not be completely satisfied.
Post Office Box 236 West Milton, OH 45383 Tel: (937) 698-1027
American National Standards Institute(ANSI): A private, non- profit organization that oversees the development of voluntary consensus standards for products, services, processes, systems and personnel in the United States. ANSI also coordinates U. S. standards with international standards so that American products can be used worldwide. The organization facilitates the development of American National Standards by accrediting the procedures for organizations who work cooperatively to develop voluntary national consensus standards.
The national “811 Call Before You Dig” program: Call 811 before digging on any project.
· Learn about the design, parts, installation needs, benefits, limits, and best uses for different types of automated gates.
· Become familiar with designing, planning, and setting up different automated gate systems, focusing on security, safety, capacity, and looks.
This section addresses the application issues of the various gate types as they relate to gate operators. It is not intended to provide specifications or instructions on how to build the various types of gates. For additional information and specifications on gate types, refer to ASTM standards as shown in each section where applicable.
ASTM F2200 is essential regarding building a gate that is intended to be automated or automating an existing gate. There are safety standards which must be incorporated into the design of automated gates, whether new or existing. Failure of the system designer to consider these standards may lead to unexpected hazards and liabilities.
Drawing 29-6005.Reference: ASTM F1184 (Industrial/Commercial, Type I)
This was a common type of gate installed following World War II through the following two decades. Overhead track slide gates have the weight of the gate panel suspended from an overhead I-beam moving on heavy duty rollers, commonly called truck assemblies.
The advantage of this type of gate is that the rollers have the weight of the gate suspended beneath them and can run across the I-beam supported well above ground, free of dirt, litter and other impediments typically found at the bottom of the fence. Most of these gates installed decades ago are still in use today, even though the gate panels may have been subject to replacement.
The first factor when designing an overhead gate is to know the minimum height clearance required. Although subject to site specific application, 14-feet is a typical clearance, much like overpass clearances on interstate highways. Another design factor is wind and ice load which must be considered when designing the footings for the support beams.
One advantage of an overhead slide gate is that the gate panel need only be the width of the required roadway opening. When considering the backspace required for the gate to move into when opening, this can be a critical factor when compared to gates with large back frame requirements (cantilever).
If a manual overhead slide gate is to later be motorized, then the need to add a minimum three- foot back frame must be remembered to accommodate the attachment points of the gate operator. The reason that overhead slide gates are not as common today is due to labor and material costs.
The overhead I-beam and the supporting posts must be heavy duty, resulting in more costly materials. The installation of an overhead slide gate requires lifting devices to install both the uprights and the horizontal beam. Despite the higher costs, these type gates still have applications that make these gates the correct choice.
Drawing 174-6001.
A true rolling gate has the total weight of the gate running
on sets of wheels (or rollers) running along the roadway surface. There is no
directional guidance to ensure the leading edge of the gate returns to the
receiving post. Although directional guidance is done subconsciously when being
operated manually, it is a limitation when trying to motorize a rolling gate.
A rolling gate will have a relatively short back frame, so that when the gate is fully closed, the back-frame portion is held between two support posts to prevent the gate panel from falling over. The other limitation to a rolling gate is the roadway surface and whether it is flat or convex.
To motorize a rolling gate, the best solution is to modify it into a V-track gate. (Drawings 30-2112 & 31-6013).
A V-Track gate has rollers supporting the entire weight of the gate. There may be a track embedded in the roadway surface or an inverted angle iron mounted onto the roadway surface that the rollers follow and provides directional guidance to the gate.
There are many methods for installing this inverted angle iron from the poor technique of nailing it directly into the roadway surface to the more professional method of creating a concrete trough into which the track is set.
Rolling gates/V-Track gates with operators installed in the typical front mount configuration require an extension or tail on the gate, typically 3 feet, to allow sufficient room for the chain to route through the gate operator and attach to both ends of the gate.
A V-Track requires a relatively flat roadway surface. If there is an extreme crown or rise in the center of the roadway for drainage, it may affect the travel of the gate as the rollers move over the roadway.
V-Track gates are rare in the Snow Belt states where snow on the ground or curved roadway surfaces make it difficult. Snowplows and gate tracks in the roadway are not compatible.
There are now many hybrids of rolling gates which are partly V-track and partly cantilever; and commonly used in warmer climates where snow and ice accumulation are generally of little concern.
The term cantilever refers to a gate that projects out into the roadway opening and is held in place by support rollers off to the side of the roadway. It is a mechanical design factor for cantilever gates that required a back-frame portion of the gate to remain within the gate support rollers when the gate is either fully open or fully closed.
The cantilever category is subdivided into two classes. The use of the term Class in the ASTM Standard for cantilever gates is not to be confused with the UL Classes of Site Applications. The UL Classes are discussed in detail in Chapter 4.
Drawing 32-6002. Reference:
ASTM F1184 (Industrial/Commercial, Type II, Class 1)
This style of gate uses two support posts and four external rollers. The weight of the gate is supported by these rollers as the gate extends out into the roadway and retracts into the open position.
This is typically supported by only two of the rollers. The specific two rollers supporting the weight of the gate varies depending on the position of the gate.
There is a vast difference in the size and quality of external rollers, from no grease fittings for lubrication to high quality ball bearing rollers. The better the roller, the easier it is to operate the gate. High quality rollers also increase the longevity of the gate.
External rollers on gates that are to be automated must have guards or covers on the top and bottom rollers. The external roller cantilever slide gate is the most difficult slide gate to move due to the weight of the gate panel shifting as the gate moves through its cycle. This affects the gate operator selected for the gate panel.
This type of gate may use two support posts, but the four external rollers are replaced by two sets of internal rollers at the top or bottom of the support posts, located inside a C-channel extrusion mounted with the face downward. The full weight of the gate is suspended from these two rollers, or truck assemblies, and at the bottom of the panel there are non-weight bearing guide rollers to prevent the bottom of the gate from moving to the side.
There is also another type of mounting that has the rollers mounted to a concrete slab under the gate and has a guide roller mounted at the top of the gate to keep the gate in the upright position.
With an enclosed track cantilever gate, the rollers, or truck assemblies, are fixed in place on the support posts, and the extruded channel moves over the rollers. The internal track cantilever does not require roller guides or covers.
In either class of cantilever slide gate, the portion of the gate frame that remains within the roller support is sometimes erroneously referred to as a counterbalance. The more appropriate term is back frame.
Use of the term counterbalance is not to be mistaken to imply that the weight of the back frame must equal the weight of the roadway opening section. Although this may create a balanced gate when it is in the fully closed position, the opposite effect occurs when the gate is fully opened.
The absence of a requirement for any overhead or roadway guidance system is one reason why the cantilever gate is the most common type of gate sold. The lower cost factor is another reason for its popularity.
A common practice throughout the fence industry when discussing the sizes of gates is to use the measurement of the roadway opening between the two posts, inside to inside dimension between the gate receiver post and the gate support post closest to the roadway opening. This would be the proper measurement for the “travel” of the gate.
It must move this distance to clear the roadway opening. However, on a cantilever gate the actual gate panel must be larger to include the back-frame of the gate.
A typical rule of thumb for a cantilever gate is to provide a back frame that is half the length of the roadway opening. For example, if the roadway opening is 20 feet, the length of the back frame would be 10 feet, making the total length of the gate panel 30 feet. (See drawing 34-6014.)
There are variations among gate manufacturers in determining this calculation which will be found in the installation instructions for each product. As an automated gate systems designer, you need to know what the formula is for the brand that will be used so the required back space can be specified to ensure the space is available.
Drawing 34-6014
The cantilever gate is the most installed commercial gate throughout the US. Its popularity is due to no restrictions about the roadway surface and the relative ease and cost of installation as compared to overhead or other types of gates.
In the sunbelt states there are other slide gate designs that are also popular using a ground track to guide the gate. However, cantilever gates are common in all areas of the country.
A restriction to a cantilever gate is the 50% longer length, which must be available at the site for the gate to open. Using our previous example, a 20- foot roadway opening will require a 30-foot space to accommodate the gate when fully open.
Any slide gate operator will work with a cantilever gate, but the higher horsepower requirements, stated by the manufacturer, must be followed. Using a gate operator with inadequate horsepower is likely to result in a reduced life span of the operator and compromise customer satisfaction.
Drawing 169-2225.
Reference: ASTM F900 (Industrial / Commercial) and ASTM F654
(Residential)
Swing gates are common and well suited for use in residential sites. They have a superior safety record compared with other types of gates in residential applications.
There are no different types or sub-classes of swing gates. Although they may differ in size and materials used, they all move through an arc, typically 90 degrees, to open and close. The
primary factor that determines how well a swing gate functions is the quality of the gate hinges and how the weight is distributed on these hinges.
When working with longer gate panels or heavier gate panels, higher quality hinges capable of supporting the gate must be used. The frequency of operation, stated as the number of cycles per hour, is another factor in determining the quality of hinges required.
Another point when considering swing gates is the support post and how well it is anchored into the ground or tied into the fence or column. The weight of the gate when moving through the 90- degree arc will create stress on the post and if it is not well anchored it will twist or bend.
It does not require any expertise to identify a poor installation of a swing gate when the panel does not travel in a level plane. At a job site, be certain to make clear notes as to whether the gates swing inward or outward, as viewed from the public side facing the secure side.
It is best to have a swing gate move away from the vehicle activating it. If this is not possible due to site conditions or gate placement, it is best to have the gate swing inward, so that the first time a driver encounters the gate it swings away from the vehicle when opening.
In accordance with the UL 325 Standard, a swing gate cannot open into a roadway or public sidewalk, or other area where the public might be expected to stand.
Drawing 35-2206
Consideration must be given to wind load when selecting a swing gate operator. A swing gate with a 90-degree arc is bound to be subject to the full wind load at some point in its travel.
The larger the gate panel, especially if it includes privacy slats or screen, the more the wind can add to the force needed to operate the gate, which may warrant the use of a heavier duty operator. Bi-parting swing gates operating as a pair are impressive in appearance and may be better suited for this application.
To operate simultaneously, two operators are used. All the accessories are usually connected to the first, or primary, operator. The secondary operator receives commands from the first operator to open, stop, close or even reverse operation when an obstruction is met during operation.
There are some standards that indicate where the hinges should be mounted on a support column, but these are explained in detail in the UL 325, ASTM F2200 and installation chapters.
The grade of the roadway in the vicinity of the swing gate must be reasonably level. With only one exception, the swing gate operator moves the gate panel in a level or horizontal plane which must be free of obstructions.
The one exception to the level plane is a unique gate operator design. The gate panel is first raised vertically and then begins to swing open while rising upward.
When fully opened, the gate panel is higher than in the closed position. This type of operator accommodates sites where there might be a curve or slight roadway incline. An example of what it can clear while opening is a standard 6-inch curb.
A vertical lift gate is a gate panel contained within a framework (typically I-Beams) that travels straight up and down to open and close a roadway. The weight of the gate panel is compensated by counterweights, so the gate operator does not have too much load to lift.
Drawing 10-2301
Alignment of the gate panel within the I-beams is maintained by a cable and pulley system much like an old drafting board. Most brands also include an emergency braking system so that the panel will jam in the track should the counterweights fail.
Vertical lift gates are sold as a system, consisting of the gate and matching operator. There must be a manual disconnect from the gate operator mechanism and a manual hand crank system to raise or lower the gate panel in the event of power or gate operator failure.
Although not as commonly used as other types of gates, there are applications where vertical lift gates are ideal. In the prison industry, where barbed wire or barbed tape is common, these items tend to get hung up on slide or swing gates. Because a vertical lift gate moves straight up and down, there is less opportunity for entanglement.
Another advantage of a vertical lift gate is that when in the closing cycle, drivers are less likely to rush a closing gate, due to the psychological image of a gate coming down on, rather than across, the vehicle. This reduces the tendency to rush a closing gate that is often done with slide or swing gates.
A vertical lift gate also can provide a quicker speed of opening and closing on wide roadway openings. Open time does not vary regardless of the roadway opening size.
To gain clearance for a vehicle, 14 feet being typical, a vertical lift gate need only open for 14 seconds (when assuming the panel travels at one foot per second). This opening time is consistent regardless of the roadway opening size. For example, a 40-foot roadway opening utilizing a vertical lift gate would still only take 14 seconds to open or close.
This type of gate does not require any clearance requirements to either side of a vertical lift gate. This is also a key advantage. At a site where there is not sufficient space to either side to slide a gate panel, the vertical lift gate can be ideal.
One marked advantage of the vertical lift gate system is that it is protected against most snow and ice conditions. This alleviates the need to shovel or clear the roadway before a vertical lift gate system can operate.
The vertical lift gate can have a contoured bottom edge to maintain a consistent spacing between the gate panel and the roadway when full closed. This custom fit of a gate panel will require drawings to be provided to the manufacturer.
The cost disadvantages of overhead gates apply as well to vertical lift gates. The support post foundations, the strength of the beams required to support the structure overhead, and the labor needed for the installation equipment result in higher costs for this type of gate system.
Like a barrier arm that rises from a horizontal position to a vertical position, a vertical pivot gate moves an entire gate panel from horizontal to vertical. To do this, there is a type of mechanical advantage, be it a spring system, counterbalance weights, or any other method to reduce the workload required of the gate operator. The mechanism to lift the gate panel requires tremendous strength.
Vertical pivot gates are sold as a system, consisting of the gate and matching operator. Some manufacturers supply the gate mechanism and the gate panel, while others supply the gate frame and allow the fence dealer to supply the gate panel. The typical time for these systems to cycle is 12 – 14 seconds with some as quick as 8 seconds.
Drawing 11-2402
Planning for wind and ice load by bracing the gate panel when in the open position. Each manufacturer will have their own standard as to when this is required, and how it is done. In order not to add to the wind load factor, the manufacturers recommend minimum signage be placed on the gate panel.
There are a few factors to plan for when using a vertical pivot gate system. One of the obvious factors is the overhead clearance required when the gate is in the raised position.
Carefully consider this when surveying the site and remember to allow for potential changes such as tree branches that grow into the vertical plane or overhead wires that could sag into the path of the gate panel. Check your local codes for electrical wire clearances. Most codes are going to require a minimum clearance of 4 feet from the travel path of the gate.
It is a good practice to install bollards on the pivot side to match the actual clearance, so a driver will have an obstacle within his field of vision. When sizing a vertical pivot gate to fit a roadway, it is important to add length to accommodate the setback.
If there are no curbs, a standard 12 inches should be added to the gate panel length. If there are curbs, add the width of the curb(s) plus the 12 inches. The typical gap between the gate panel and the roadway is 5 inches.
Like a vertical lift gate, an advantage for a vertical pivot gate is that it can work well with uneven roadway surfaces. A slide or swing gate does not have this ability to have the bottom of the gate panel custom fit to match an irregular surface such as slopes, swales, curbs, or even railroad tracks. With proper field dimensions an even gap can be maintained between the gate and the roadway.
Drawing 170-2410
If you are designing the gate to fit a curb, swale or sloped drive and a clear opening is a critical factor, the amount of drop in the gate below the mounting pad level will end up past the face of the operator when it is in the raised position. It is common to provide the manufacturer some specific drawings to clearly show these requirements.
Another advantage of a vertical pivot gate is that it can take a relatively large gate panel without requiring much back-frame space. Although it will vary by each manufacturer, a typical operator housing is 5-10 feet in length.
Vertical pivot gate systems also work well in areas with snow or ice conditions. This minimizes the need to clear the roadway before a vertical pivot gate system can operate.
An overhead pivot gate is like a one-piece garage door. It is a one-piece constructed gate panel that is counterbalanced with springs and runs on a heavy-duty track system like a garage door on a residence using a trolley style operator.
Drawing 36-2701
An overhead pivot gate is like a one-piece garage door. It is a one-piece constructed gate panel that is counterbalanced with springs and runs on a heavy-duty track system like a garage door on a residence using a trolley style operator.
These gates are often used in parking garages where a slide or swing gate are not feasible, or where there are height restrictions. Like vertical pivot gates and vertical lift gates, the overhead pivot gate can have a contoured bottom edge to maintain a consistent spacing between the gate panel and the roadway when fully closed.
This custom fit of a gate panel will require drawings to be provided to the manufacturer. ASTM F2200 provides guidance pertaining to covering exposed rollers along with the allowable openings in the gate.
Barrier arm gates (aka parking gates) are often used for controlling vehicles entering a property or parking area. These may be used alone for controlling traffic flow, or in conjunction with another type of gate for increased security.
Barrier arm gates provide a much faster cycle time from close to open and back to close. Some barrier arms may open in 2-3 seconds, although larger gates may run slower. This provides better traffic control and minimizes the opportunity for “tail-gating” through the gate system.
·
Understand and apply the design and construction standards set by ASTM
F2200 and the Manual on Uniform Traffic Control Devices (M.U.T.C.D.) for
automated gate systems, ensuring compliance, safety, and security in design and
installation.
·
Apply safety measures required by ASTM F2200
and M.U.T.C.D. to make sure gate installations are secure, using design ideas
that meet these standards and rules.
ASTM F2200 is the standard by which
vehicular gates that are intended to be automated should be fabricated and
installed.
There are two important safety standards that affect automated gate systems, UL-325 and ASTM F2200.
UL-325 is primarily directed at the gate operator function and operation, although there are specific installation parameters that must be followed. This is discussed in Chapter 5.
ASTM F2200 is directed at the gate construction and installation, rather than the operator. This is the standard by which automated vehicular gates are fabricated and installed.
ASTM F2200, which became effective on July 10, 2002, includes design and construction standards for gate designers, fabricators, and installers. ASTM F2200 applies only to the construction of gates that are intended to be automated. If a manual gate is changed to an automated gate, the gate must conform to the current standards before it is automated.
Existing automated gates, when the operator requires replacement, must be upgraded to conform to the provisions of this specification in effect at the time of replacement.
When encountering a non-compliant installation, the recommendation is to notify the customer of the deficiencies, in writing, and to bring the gate up to the current standards before service work is performed.
The ASTM F2200 standard does not apply to
pedestrian gates or gates not intended to be automated.
A Coalition Committee was formed with the participation of representatives from AFA, NOMMA, DASMA, and IDA which resulted in writing and acceptance by ASTM of Standard F2200.
Any gate built with the intent to be automated, or any gate built previously which is later to be automated, must meet this standard.
F2200 History
· Provisions initiated in 1998 by AFA, DASMA and NOMMA
· Industry input solicited throughout development
· Turned over to ASTM in 2001
· Became ASTM Standard for Construction of Gates Intended to be Automated on July 10, 2002
Automated vehicular gate compliance with the ASTM F2200 standard has the following objectives:
· Improve safety
· Increase security, balanced with safety
· Raise industry awareness
Automated vehicular gates are, by design, intended to provide security and to limit access to property. This can result in a delicate balancing act between security and safety.
The need for security does not offset responsibility
to prevent injuries due to entrapment, from protrusions or pinch points, or
simple child’s play. Knowing, understanding, and consistently following the
ASTM F2200 Standard, and the UL 325 Standard for gate safety, is a fundamental
aspect of automated gate systems designer professionalism.
Like UL 325, ASTM F2200 is a voluntary standard. This is a legal distinction only and does not mean compliance is optional. All that is meant by the term voluntary standard is that the provisions do not carry the force of law.
Such standards are created by industries rather than government and set forth best practices. While these standards are designed to create a consensus on critical safety measures related to the associated products, a practical consequence is that they can be used as the basis for determining liability in the event of death or injury.
As a voluntary standard, ASTM F2200 gate manufacturers can choose to provide compliant or non-compliant products, unless this is required by state or local codes that require them to do so or is part of the project specification. A fully compliant automated vehicular gate system is one in which products conforming to UL 325 and ASTM F2200 standards are provided and installed according to the manufacturers’ instructions.
This chapter will also address the impact of new building and fire code regulations and how they will enforce the UL and ASTM standards.
· Published September 2002
· Further development continues by ASTM F14 and AFA/NOMMA/DASMA
ASTM F2200 standards are based on the type
of gate and the applicable gate operator. The standard describes construction
of the gate itself based on its operation. Gate types that are not specifically
described within the standard are still subject to all applicable provisions.
The standard includes a “general requirement” section which addresses construction and installation standards that are to be applied to all types of gates. The standard also includes specific sections for each type of gate:
· Horizontal Slide Gate
· Horizontal Swing Gate
· Vertical Lift Gate
· Vertical Pivot Gate
· Overhead Pivot Gate
These provisions apply to all types of gates. Gates that are not specifically described within the standard are still subject to these general provisions. The provisions include:
·
Gate
systems are to be provided with auxiliary supports to prevent a gate from
falling over more than 45 degrees from its vertical plane when detached from
supporting hardware. See drawing 13-2102 and following drawings.
Drawing 13-2102
Drawing 175-2116
Fall Over Support, Swing Gates Drawing 14-2207
There should be no protrusion greater than one-half inch on the bottom or vertical edge of the gate. No protrusion may have sharp edges regardless of length.
Drawing 16-2004
Drawing 15-2002
The above gate is NOT in compliance!!
The previous gate COMPLIES!!
The gate below does NOT!
· Allowable protrusions are top pickets and top decorative designs provided they are in a vertical plane with respect to the gate; gate locks, wheels and positive stops on horizontal slide gates; bottom retainers in Class IV horizontal slide gates; and positive stops at the top of vertical lift gates.
· Automated gates need to have all gate latches disabled.
· The gate must be balanced so that it does not open or close on its own when disconnected from the operator.
· For pedestrian access in the vicinity of an automated vehicular gate, a separate access opening shall be provided.
Drawing 171-2601
· Barbed wire cannot be installed at a height lower than six feet, and barbed tape cannot be installed a height lower than eight feet for a gate panel intended to be automated.
Drawing 17-2003.
· A manual gate shall be upgraded to conform to the provisions of ASTM F2200 when automated.
· When the gate panel in an automated gate system requires replacement, the new gate shall conform to the provisions of the current ASTM F2200 standard.
· Existing automated gates shall be upgraded to the current ASTM F2200 standard when the operator requires replacement.
As previously indicated, the ASTM F2200 standard contains provisions for specific types of gates. The following will identify the guidelines based on gate type.
· All weight bearing rollers should be covered or guarded unless they are eight or more feet above ground level.
Drawing 18-2103.
· Openings shall be designed, guarded or screened to prevent reach through and must prevent a 2-1/4” sphere from passing through from the bottom of the gate panel to the top of the gate panel, or to a maximum height of 6 feet above grade, whichever is less.
Drawing 9-2101.
Draw in post, less than 2.25” gap.
· There shall be no gap between the gate and a stationary object nearest to the roadway (such as a gate support post) exceeding 2Ľ inches unless that stationary object is greater than 16 inches from the gate frame.
Drawing 19-2104.
· Positive stops are required to limit travel to designed fully opened and closed positions.
Drawing 20-2110.
· Gates must be designed with sufficient stability to assure the gate properly enters the receiver guide.
· Single panel receiver guides must be recessed behind the leading edge of the receiver post or a fixed object unless the guides are eight or more feet above ground level.
Drawing 21-2105.
· Receiver guides installed on either panel of a bi-parting slide gate must have a leading edge with a minimum projected area of nine square inches.
Drawing 22-2106.
· Gates shall be designed, constructed, and installed so as not to create an entrapment area between the gate and the supporting structure or other fixed object as the gate moves toward the fully open position.
· The width of the distance from the center hinge point to the edge of the column, pillar or wall shall be less than 4 inches or cover this area with entrapment protection.
Drawing 23-2202.
· Except for the hinge point, the distance between a fixed object and the gate when in the open position shall be more than 16 inches or cover this area with entrapment protection.
Drawing 24-2201.
· Class IV vehicular gates shall be designed constructed and installed in accordance with security related parameters specific to the application in question.
· Although swing gates do not have any restrictions to prevent reach-through like the slide gates, they do have a restriction on the picket per ASTM F 2200. As a swing gate rotates pickets below the frame could create a tearing effect should someone be caught under the gate panel.
· No pickets are allowed below the bottom frame of the gate panel, and other protrusions are restricted to no more than 1/2 inch.
Drawing 23-2202
Drawing 169-2225
Drawing 24-2201
This gate is not compliant!!!
Drawing 25-2208
· All openings in the gate must be designed to prevent a four-inch sphere from passing through the gate.
· There can be no gap exceeding four inches in the frame of the gate panel. See drawing 10-2301.
· Framing members must be smooth.
· Positive stops are required.
· Class IV vehicular gates shall be designed constructed and installed in accordance with security related parameters specific to the application in question.
Drawing 10-2301
· All areas of the moving gate panel, from the bottom of the gate to the top of the gate, or a minimum of 72 inches above grade, whichever is less, and that pass by a fixed stationary object, and the area of the adjacent fence that the gate covers during the travel of the gate, shall be designed, guarded or screened to prevent a 2-1/4” sphere from passing through such areas.
Drawing 11-2402.
· There can be no gap exceeding 2-1/4 inches in the frame of the gate panel.
· Framing members must be smooth. The gate must be designed with sufficient lateral stability for the gate to properly enter receiver guide.
· Class IV vehicular gates shall be designed constructed and installed in accordance with security related parameters specific to the application in question.
· All rollers should be covered or guarded unless they are eight or more feet above ground level.
· All openings in the gate must be designed to prevent a four-inch sphere from passing through the gate.
· There can be no gap exceeding 2-1/4 inches between a fixed stationary object and the gate frame.
· Framing members must be smooth.
· Positive stops are required to limit travel of the gate to the fully opened and closed positions.
· The jamb and track counterbalance system must support the weight of the gate in any position.
· Class IV vehicular gates shall be designed constructed and installed in accordance with security related parameters specific to the application in question.
NOTE: Several sections of the Door & Access Systems Manufacturers Association (DASMA) Technical Data Sheet 380 have been used below to provide this information. We wish to thank them for their assistance and continuing support of this and all AFA schools.
These data sheets, and many others applicable to the gate operator industry, are available from the DASMA website at: www.dasma.com.
A U.S. Department of Transportation regulation sets federal guidelines on what must be done on streets and highways for traffic control devices. A revision to that regulation included new wording that impacts gate operators controlling access from a public road regarding signage. The changes became effective on January 1, 2012.
This federal regulation is available at: https://mutcd.fhwa.dot.gov.
State regulations pertaining to MUTCD can be found at:
https://mutcd.fhwa.dot.gov/resources/state_info/in dex.htm
The responsibility for the design, placement, operation, maintenance, and uniformity of traffic control devices shall rest with the public agency or the official having jurisdiction, or, in the case of private roads open to public travel, with the private owner or private official having jurisdiction.
The relevant sections of this regulation to the gate operator industry are:
Section 2B.68: Gate arms, if used, shall be fully retro reflectorized on both sides, and have vertical stripes alternately red and white at 16-inch intervals measured horizontally (like railroad crossing gates).
Section 2B.58: Rolling sections of fence, if used, shall have either a horizontal strip of retro reflectorized sheeting on both sides of the fence with vertical stripes alternating red and white at 16-inch intervals measured horizontally to simulate the appearance of a gate arm in the horizontal position, or one or more Type 4 object markers (see Section 2C.66), or both. If a horizontal strip of retro reflectorized sheeting is used, the bottom of the sheeting shall be located 3.5 to 4.5 feet above the roadway surface. (Note: There is no stated vertical width of the striping tape). See drawing. An alternative to the reflective tape is a Type 4 object marker.
Section 2C.66 describes this alternate.
The minimum mounting height, measured
vertically from the bottom of a Type 4 object marker to the elevation of the
near edge of the traveled way, shall be 4 feet. See
drawing for examples of object markers. This marker may be less objectionable
to the customer if the installer is forced to comply with this government
regulation.
Drawing 26-7003
Drawing 27-7001
Drawing 28-7002
Knowing and understanding the standards regarding automated vehicular gate systems is one of the most important responsibilities of the automated gate system designer. In many instances, designers will encounter resistance from customers to fully compliant gate systems for reasons of cost and aesthetics. The professional designer must be capable of educating customers regarding the importance of compliance with ASTM F2200 and UL 325 standards.
At times, designers may be asked to automate non-compliant gates. The designer should be able to explain to the customer the need for bringing the gate into compliance with ASTM F2200, and ensure the operator is installed in full compliance with UL 325.
· International Building Code
· International Fire Code
· Residential Building Code
The previous codes have now incorporated both the UL 325 and ASTM F2200 Standards as a part of their standards. It will take some time for the Fire Marshals and Codes Enforcement Officers to learn about these standards, but it will begin to happen and occur more and more frequently. There is no waiver of these standards, so avoid getting caught and do the installation to standards and gate operator manufacturer’s installation manual right from the start.
· ASTM F900 - Industrial/Commercial Swing Gates
· ASTM F1184 - Industrial/Commercial Horizontal Slide Gates
· ASTM F1911 - Installation of Barbed Tape
· UL 325 - Standards for Door, Drapery, Gate, Louver, and Window Operators and System
·
Explore different types, styles, and features of gate operators.
·
Understand how to choose and compare the right gate operator based on
specific needs like gate size, weight, frequency of use, environmental
conditions.
Early gate operators were modified commercial door jackshaft operators placed on a support stand and located inside a rainproof housing. Many door operator manufacturers still make gate operators today, although there are now many companies which make only gate operators.
Despite the wide range of brands, types, and models of gate operators, they all have some fundamental principals in common. They are designed to match a specific type of gate, and to open and close that gate in a safe manner.
Gate operators that have been tested and found to be compliant with the UL 325 standard, will have a UL 325 Label (or ETL). A summary this standard is presented in the UL 325 Chapter.
When the main changes for vehicle gate systems UL-325 went into effect in March 2000 it became clear that a standard needed to be written addressing the design of gates which are to be automated. A Coalition Committee was formed with the participation of representatives from AFA, NOMMA, DASMA, and IDA. This resulted in the creation of the ASTM Standard F2200.
Any gate built with the intent to be automated, or any existing gate which is later automated, must meet this standard. Failure to do so could result in the installing company, and the gate operator installer, being liable should a personal injury accident occur. A summary of the ASTM F2200 standard is presented in Chapter 3.
A system designer should know that specific installation instructions are contained in almost every gate operator installation manual. Once the designer’s company selects what brand and model of gate operator to provide, the designer and installer are then required to comply with that manual’s installation instructions. Always follow the manufacturer’s installation instructions.
Regardless of a designer’s rank or tenure with the company, the designer must be able to identify when a system is not compliant with the existing UL 325 or ASTM F2200 standards. Should this occur, bring the matter to the attention of the proper authority within the company before placing the gate operator system into operation.
The final responsibility remains in the hands of the designer of the system. The most common cause of personal injury which occurs at automated gates is in some manner associated with a control device to open the gate being located at or near the gate operator or the gate panel. Hence, the six-foot no-control-zone. (See Drawing 12-2006, next page)
Drawing 12-2006
Bi-parting gate systems consist of primary and secondary gates that work in unison, opening and closing simultaneously. In these systems, the primary gate controls the functionality of both gates. Manufacturers use various methods to accomplish this simultaneous operation. Consult the manufacturer’s installation instructions to determine the wiring requirements for each make and model.
Single Swing Gate
Drawing 39-6022
Gate operators are available in different voltages and may use AC or DC voltages. The electrical properties of these are found in Chapter 6. The following is a review of these options.
Operators using AC motors come in many different sizes, and configurations, from simple light duty residential machines to heavy duty industrial operators designed for large, heavy gates. Motor horsepower, gate capacity (length of travel and weight of gate) and what supply voltage may be available are things to consider when you are selecting an operator.
AC Power, Single Phase: All residential and commercial construction provides both 115 volts and 230-volts, single phase power in the home. 115VAC power is the common for residential and multifamily applications.
208V or 230VAC may be found in commercial and industrial applications. It would be a rare exception to find three phase power in a residential location.
AC Power, Three Phase: Commercial and industrial sites may have 3-phase power available. 3-phase power can be provided in 208V, 230V, 460V or 575V (Canada).
Three phase power is intended for heavy duty, high horsepower motors and is a better voltage for the gate operator, if available.
Since 208 or 230 volts are the only voltages that can be either single or three-phase, the installer should always clarify which phase the voltage will be. It is not practical to convert an operator from single phase power to 3-Phase power.
DC Motors: Operators using DC motors have become popular in residential and commercial gate systems. These utilize battery supported DC power to run the operator. The batteries may be charged either using AC power or solar power.
Some of the advantages of a DC operator include:
a) Battery backup capability.
b) Controlled slow start/slow stop operation.
c) Compact design.
There are different types of DC operators available. Many light duty residential operators use DC power, but there are also heavy-duty operators available. These provide similar operation, but use slightly different technologies:
DC Operators - Transformer Run, Battery
Back Up
The DC operator converts incoming primary power (AC voltage) to DC voltage (nominally 12 or 24 VDC) to run the motor and maintain charge on the batteries. The motor can draw power from the supply voltage and/or the batteries.
This is the simplest and most efficient means of providing full function operation when power fails. In the event of loss of power, the DC operator continues to run on battery power until power is restored.
DC Operators - Battery Run, Battery Back
Up
This DC powered operator is completely powered by batteries both in normal operation (when an AC or alternative power source is available) and in power fail situations. The power source is only used to keep the batteries charged and provide a small amount of idle current to the system to power the various circuits that must be monitored when not moving.
These systems are excellent candidates for alternative renewable power sources such as solar and wind generators provided the system is designed to survive the potentially frequent occurrences where power is unavailable.
These systems are also excellent candidates to run low voltage wiring to power the operator. The primary drawback for these types of operators is the number of cycles since high cycles may drain the batteries before the charging system can replenish them.
This system also suffers from the issue of aging batteries described in the previous section. However, since the batteries are the only source to power the motor, if these operators are cycled more frequently, they may very well wear out the batteries sooner. To overcome this and other limitations, larger batteries can be used but can add cost and take additional space.
Gate operator manufacturers provide a rating for each model they offer. This rating relates to the size and weight of the gate panel, and the maximum number of cycles it is designed to handle.
This rating allows the installer to verify the gate operator matches the application. Although the size of the gate panel is known, the weight may be harder to determine.
The frequency of use is often the critical factor when selecting the gate operator. The number of cycles per hour is the best indicator for the workload of the gate operator.
Do not underestimate the cycle of operations required. It is important to know the difference between a maximum number of cycles per day versus the number of cycles at the peak traffic times.
For residential or multi-family applications:
· Count the number of houses or apartments the gate/s will serve.
· Multiply this X 2.5 to determine the number of vehicles behind the gate.
· This provides an indication on how many people may pass through the gate between 6- 8AM as they head to work.
· This is your peak gate cycle.
For commercial or industrial sites:
· Count the number of storage units, bay doors, parking spaces whatever the potential user number might be
· This would be the minimum usage number to start with,
· Are they 2 shifts that overlap?
· This will give you an idea on the peak gate cycle.
The peak traffic time cycles should be used to determine the model/power of the gate operator to use. Read each manufacturer’s rating and do not misapply an operator in the wrong application.
Residential gate operators are intended for low cycle applications with relatively light weight gates. These operators will not operate well if they are misapplied in high cycle applications or are installed on gates with heavy workloads due to gate weight, the poor quality of the hinges, or wind load.
Commercial/Industrial gate operators are designed to handle larger sized and weight gates with expected high duty cycles. The method of transferring the power of the motor to the output point (belt drive, gear drive, or hydraulics) has a larger impact on the capabilities of the operator than the slight difference in horsepower ratings.
Weather conditions are another factor that must be considered when selecting a gate operator to match the application. Almost all gate operators are affected by extreme hot or cold weather to some degree, but extreme cold has more impact on certain types of gate operators than others.
Conversely, extreme heat may lead to temporary shutdown due to thermal overload tripping. Both extremes can affect a DC operator’s ability to recharge and store battery energy.
Gate operators using gear reducers, or hydraulics, are more likely to be impacted by cold weather because the fluids used in hydraulics and gear reducers may thicken as the temperature drops. Manufacturers now use oil which is unaffected by temperatures from -40° to 185° F.
Heaters should be considered when selecting these types of operators in cold weather conditions. Always consult the manufacturer specifications for proper hydraulic fluid or oil to be used when adding or changing the oil.
For applications that use batteries in cold weather conditions, a heater may be needed to help prevent power loss to the batteries. The lower the temperature, the less power is available in the battery.
Some types of gates that work well in one climate may not be as suitable for conditions found in other climates. For example, a surface mounted V-Track gate might be suited in warmer climates where snow and ice removal are not necessary, but in colder climates, snowplows can damage both the gate system and the plow.
Gate operators must be designed to allow for the manual operation of the gate in case of power failure, entrapment, or operator malfunction.
Fail-Secure –The release mechanism can be a lever, a switch, a key, a crank, or any device that places the operator in manual operation. This type of system is often referred to as fail-secure because if there is a power failure, the gate cannot be manually moved until the release mechanism is engaged.
Fail-Safe –In this type of release, a power failure, or simply switching power to the operator OFF, will allow the gate panel to be pushed open without using any other means to disengage the drive system. In both type systems, manual movement of the gate will not affect limit settings.
The fence industry views a gate from the non-secure side looking inward. This perspective is often called outside looking in. This is the opposite approach used by the gate operator industry which refers to the hand of a gate operator from the secure side looking out, and the side of the roadway the operator is mounted. This is commonly called inside looking out.
There is an occasional application where the gate operator may not be mounted on the secure side of the fence. The more technical description of inside looking out should be stated as viewed from the same side of the fence as the operator. Most of today’s gate operators can be changed from one hand to the other.
Drawing 44-1001
Gate operators are available to match each type of gate. While remaining generic, the intent of this section is to provide the installer with the basic information and principals of operation about each type of gate operator.
Slide gates are a common type of automated gate for commercial/industrial applications. While swing gates require a 90-degree arc for gate movement, slide gates do not.
Slide gates do, however, require a space to open into, and this space is called the back plane of the gate. These are space considerations to plan for when using a slide gate.
Most slide gate operators may be pad mounted or post mounted. There is no mechanical difference in the two methods of installation.
Per the UL 325 standard, in residential (Class I or Class II) applications, the gate cannot move faster than one foot per second. Commercial/industrial applications (Class III or Class IV) may have gates moving at higher speeds.
It is important in the installation of a slide gate operator to align the gate operator parallel to the gate. Misalignment will cause the chain to feed over the sprockets at an angle and cause premature wear.
Misalignment adds extra workload to the gate operator’s drive mechanism. The size of the drive chain varies according to the expected workload of the gate operator.
Heavier loads require a heavier gauge of drive chain. There are several different types of drive trains for slide gate operators. Some of these same design concepts are used in swing gate operators previously discussed in this chapter.
Belt and pulley type slide gate operators use a motor, which rotates the drive pulley, which in turn drives a larger pulley for both speed reduction and to create torque. Automotive type belts are used in this first reduction along with some type of spring compression for adjustment of a clutch to allow for slippage.
Editor’s Note: A clutch, pressure relief or inherent force limiting means cannot be used as an entrapment protection device on any slide gate operator as per UL325. In most models there will be additional levels of reduction to further decrease speed and increase torque at the output shaft.
The output shaft will have a drive sprocket which will drive a continuous feed of chain between two idler sprockets that are mounted below the plane of the drive sprocket and slightly off to each side. The two ends of the drive chain are attached to the ends of the gate, and the direction of rotation of the drive shaft establishes the direction of gate movement. The gate is always being pulled whether it is being opened or closed.
Limits are controlled in a variety of ways. One design uses a timing chain driven by a secondary sprocket on the drive shaft rotating a timing sprocket which in turn rotates a limit shaft.
Limit nuts traveling on the limit shaft mechanically trip
limit switches to stop the gate at the desired position. There must be a
minimum of two limit switches, one at each end of the limit shaft. Additional
limit switches may be necessary for auxiliary control devices.
Some operator designs rely on motor run times, positioning systems, or some type of counter (usually magnetic) or programmable setting to determine the limits of travel. Operators that use these types of systems do not have timing chains, timing sprockets, limit nuts or limit switches. The operator travel in these operators is set electronically rather than mechanically.
A gearhead type slide gate operator uses a motor, typically running at 1,750 RPM, which rotates an input shaft to a gearbox. The mechanical reduction is established by the gear ratio, which could be anywhere from 10 to 1 and as high as 60 to 1.
Since a gearbox will not allow any slippage, another type of clutch mechanism may be used with this type of gate operator.
Editor’s Note: A clutch, pressure relief or inherent force limiting means cannot be used as an entrapment protection device per UL325 on any slide gate operator.
A gearhead operator uses the identical method as a belt and pulley to transfer the force to the gate panel. The output shaft will have a drive sprocket that will drive a continuous feed of chain between two idler sprockets that are mounted below the plane of the drive sprocket and slightly off to each side.
The two ends of the drive chain are attached to the ends of the gate, and the direction of rotation of the drive shaft establishes the direction of gate movement. The gate is always being pulled regardless of whether it is being opened or closed.
For manual operation of the gate in case of power or operator failure, there is a manual lever that disengages the gear reducer from the drive shaft. With high gear ratios, 40:1 for example, it would be impossible to manually move a gate by back driving through the gearbox.
With some of the newer lower gear ratios,10:1 for example, the gate can be back driven.
When disengaged, the gate panel can be moved, but in doing so must still rotate the output shaft and this does create mechanical resistance. Manual operation of the gate will not affect the limit settings.
A hydraulic drive slide gate operator uses an electric motor, which runs a pump to create hydraulic pressure. When hydraulic fluid under pressure is applied to a hydraulic motor, the motor will rotate like an output shaft.
Hydraulic driven gate operators create more torque with less wear and tear than belt and pulley, or gearhead, driven gate operators.
The direction of the fluid within the hydraulic system will establish the direction of rotation of the hydraulic motor. The hydraulic motor has an output shaft attached to a drive wheel.
The force of the drive wheel exerted upon a drive rail can be set by an adjustable compression spring.
All hydraulic drive operators will have two wheels. Some models use two wheels driven by two hydraulic motors. Another method is a combination of one wheel driven by a single hydraulic motor along with an adjustable idler wheel.
The viscosity of the hydraulic fluid will vary according to the ambient temperature. Most manufacturers will recommend a heater and thermostat for use in cold climates, to keep the fluid within acceptable temperatures.
In case of power or operator failure there is a mechanical disconnect lever that removes the drive wheels from the drive rail. When disconnected, there is no component of the gate operator being driven or rotated, thus movement of the gate panel is easier with this type of gate operator
In cold climates, steps may be necessary to ensure the reliable operation of the gate system. Rail guards can be installed to prevent snow and ice from accumulating on the drive rail. Slippage concerns can be minimized by the proper adjustment of wheel tension.
Due to the torque created by a hydraulic gate operator, they are typically pad mounted, but it is possible to post mount these when necessary. The hydraulic drive units can produce enough force to run a gate at speeds greater than one foot per second.
Although the first gate operators to travel at speeds more than the standard one foot per second were hydraulic operators, there are non-hydraulic gate operators now available with faster travel speeds. Some have adjustable speeds of up to three feet or more per second. Consult the manufacturer’s instructions to determine each unit’s capabilities.
Evaluate the needs of the customer and the size of the roadway opening to determine if such a unit is applicable to the site application.
Like a hydraulic drive, there is a rail mounted to the gate. This rail is provided with teeth. This is called the “rack”.
The drive wheel on the operator is a pinion which interacts with the drive rail teeth.
The time for a swing gate to move through the 90-degree travel arc is between 12 to 18 seconds, depending on the operator. The length of the gate panel has no bearing on the amount of time to cycle, but the longer the gate, the higher the speed of the gate when that speed is measured at the end of the gate.
There are swing gate operators that can handle gates up to 30’ wide. While possible, a gate this large creates a large area of sweep as the gate travels between the open and closed positions. It is common to split large gate openings in half and use a dual operator system rather than trying to use one large gate and gate operator.
For example, a 16-foot roadway opening would be designed with 2 gate panels, each 8 feet in length. In many cases at residential sites for aesthetics purposes, even a 12-foot opening may use a pair of bi-parting gate panels.
Swing gate operators are produced with various types of drives just as in the slide gate section. These include:
· Belt and pulley drive
· Gearhead or worm gear drive
· Hydraulic piston drive
· Rack & pinion gear drives
· Screw drive
There are many design configurations for swing gate operators to move the gate. Here is a review some of these.
This type of swing gate operator uses an electromechanical drive shaft that rotates a fixed crank arm. The fixed crank arm is attached via a pivot point to an extension arm which is attached to the gate. As shown in the drawings, when the gate is closed, the crank arm and the extension arm are in a nearly straight alignment.
Although the rotation speed of the vertical shaft is a constant RPM, the mechanical principal of the extension arm with the pivot point on the crank arm results in a variable speed of the gate. The gate begins to open slowly and builds up speed to the point the crank arm and extension arm reach a 90 angle to each other.
Drawing 40-2226
The gate begins to slow down as the extension arm begins to fold over the crank arm. This is an intentional design to start the gate slowly, build up speed, and then reduce speed just before stopping.
The aesthetics of the smoothly moving gate is nice, but the prevention of a shock load to the drive system of the gate operator is the major benefit. Most swing gates are designed to move the gate through a 90-degree arc, but some harmonic arm models can move the gate up to a 120-degree arc.
The length of the crank arm as measured from the vertical shaft to the pivot point affects the degree of opening.
Harmonic type swing gate operators may be pad mounted or post mounted. They are self- contained drive mechanisms with controls that mount behind the gate and just off to the side of the roadway.
Drawing 81-2215
These types of operators do not require a separate post or pad mount application. Instead, the operator mounts to a standoff bracket from the gate post or column.
It is important that the mounting dimensions and pivot points that are given in the installation manual are followed closely. There is little tolerance for mistakes to be made in these measurements.
An advantage of this style operator is that it is relatively easy to configure the gate to either swing the gate inward pulling the gate towards the property, or outward pushing the gate away from the property. This requires
the proper mounting dimensions. See drawings below
The two types of linear actuator operators are hydraulic pistons and screw drives.
Hydraulic Piston: Extending and contracting the length of the actuator is done via hydraulic pressure and a piston, or cylinder. The motor, the valves, and the hydraulic fluid are all contained within the unit.
Ambient temperature range and the frequency of operation should be considered before using these types of operators. Manufacturers use different methods to control the open and close limits on these operators.
Screw Drive: Extending and contracting the length of the actuator is done with a combination of a rotating screw and traveler mechanism. The motor and gears are contained within the unit. Limit settings vary by manufacturer.
Common to both types of actuators is that the drive mechanism and the controls are generally two separate units and are mounted separately. The internal mechanisms of both types are generally not repairable in the field.
Drawing 42-2217
These are a unique type where the drive shaft of the operator is mounted directly under the gate and attached to the bottom crosspiece. One type uses hydraulic pressure to rotate the gate panel.
An advantage of this type is that no outward appearance of the operator is present, but a disadvantage is the need to have exact dimensions and installation coordination with the gate installation.
This is a unique type of swing gate operator that first raises the gate before it begins to swing open. When the gate reaches the fully open position, the gate is 12 inches higher than when it was in the closed position.
The advantage of a column mount operator is that it can work with larger columns.
The drawings below may be used as templates for future gate operator installations. These drawings may serve as a site checklist to review issues relating to required equipment, accessories and site conditions which could affect both the material costs and installation time on the job site.
SEE FOLLOWING PAGES
·
Learn about entrapment zones and the proper entrapment devices to
protect these areas.
·
Understand and apply UL 325 standards for designing and installing
automated gate systems, including key parts, rules, and the importance of
warning signs to ensure safety and compliance.
·
Maintain proper records for UL 325 compliance, know the necessary
documents for audits, and stay updated on changes to the standards and their
impact on gate operators.
SPECIAL NOTE: This section addresses information contained within a document published by Underwriters Laboratories and is protected by appropriate copyright laws. This chapter is intended to educate the gate operator installer regarding the duties and responsibilities created by the UL 325 Standard.
This chapter is not intended to educate a gate operator manufacturer as to how to comply with UL 325 for recognition of the manufacturer’s product. This section, as written, pertains specifically to United States agencies.
If the reader operates outside the United States, consult the applicable local regulatory agencies. For more information, or a copy of the current UL 325 Edition, contact Underwriters Laboratories, Inc., 333 Pfingsten Road, Northbrook, IL 60062-2096; Telephone: (847) 272-8800.
Underwriters Laboratories, Inc., (UL) founded in 1894, is an organization formed to establish, maintain, and operate laboratories for the examination and testing of devices, systems, and materials to determine their relation to hazards to life and property, and to ascertain, define and publish standards, classifications and specifications for materials, devices, products, equipment, constructions, methods, and systems affecting such hazards.
UL is not a government entity but works closely with the Consumer Product Safety Commission (CPSC) to ensure electrical products are as hazard free as possible in the interest of public safety. While there is no federal law mandating compliance with UL 325 for gate operators, some state laws and local ordinances reference the standard and require compliance.
It is the responsibility of the gate system installer to ensure that a UL 325 labeled/listed gate operator is provided, and that the installation is designed and installed in compliance.
1. International Building Code (IBC) – 2009 edition and later
2. International Fire Code (IFC) – 2009 edition and later
3. International Residential Code (IRC) – 2012 edition and later
The above codes are published by the International Code Council (ICC.) The codes must be adopted by a state or local jurisdiction to have the force of law. These codes supersede both the written specifications and contracts between the seller and the purchaser.
The first edition of UL 325 was written in 1973. A major revision of the UL 325 Standard that significantly affected gate operators was the Fourth Edition, which went into effect in March 2000.
The UL 325 standard changes from time to time. Always check and follow the manufacturer’s installation instructions to ensure compliance with the latest version of the standard. The latest revision as of publication of this study guide became effective August 1, 2018.
The manufacturer of a gate operator voluntarily agrees to submit products for UL 325 testing. Although the best-known testing facility may be Underwriters Laboratories, there are other Nationally Recognized Testing Laboratories (NRTL) such as Intertek (ETL), Metlabs, and CSA that can perform product safety testing.
When a submitted product meets the UL standard, the product is labeled and listed, and the manufacturer may place the “mark” in their specifications, on the product, literature and packaging.
It is incorrect to state a device is UL approved. It is only correct to state a device is labeled and listed, and in the case of a gate operator, it would be labeled and listed to UL 325.
A manufacturer that claims that a gate operator is compliant with UL 325 is not the same as the gate operator being labeled and listed to UL 325. Look for a mark on the label of the product indicating listing to UL 325.
A designer of an automated gate system takes on a key responsibility in safeguarding the performance of a gate system. Adhering to UL 325 and following the manufacturer’s instructions help to ensure the safe operation of a gate system and protects the end user and the public.
A certified gate system designer should know the information contained within this chapter and understand the design requirements for the system to meet the UL 325 Standard. If a gate operator has been labeled and listed, the instructions contained within the gate operator’s manual are mandates to the automated gate system designer and must be followed for the system to be UL compliant.
It is common for end users to request certain entrapment protection features be bypassed or declined altogether. This is not an option for either the gate system designer or the installer.
Waivers are of no practical use. End users may not have the same understanding of the hazards associated with automated vehicular gate systems and could claim they would not have asked for the entrapment protection devices to be bypassed or declined had they been fully advised of the hazards.
As an automated gate system designer or the gate operator installer, the courts may hold the installer liable as the expert who is expected to do what is correct regardless of a request from the end user.
UL 325 addresses entrapment protection devices only as they may be applied to the welfare of personnel, and not vehicles. For this reason, there is no mention of vehicle detectors in UL 325, as they would not serve to protect an individual. This is not to say that vehicle detection systems are not an integral part of a gate operator system, they just do not apply to entrapment as defined by UL 325.
A vehicular gate operator or vehicular barrier (arm) operator shall:
· Have provisions for, or be supplied with, a minimum of two independent entrapment protection means for each entrapment zone.
· Operate only after installation and enabling of the minimum number of acceptable entrapment protection means.
· Be supplied with instructions regarding entrapment protection means.
· EXCEPTION: An operator for a barrier arm not intended to move toward a rigid object closer than 16” and does not have pinch points between moving parts.
A gate operator installed using monitored external entrapment protection Types B1 or B2 to comply with UL325 shall monitor for the presence of every entrapment device at least once during each open and close cycle. Upon monitoring, if a device is not present, or a fault condition occurs, the operator shall function only with constant pressure as required by the standard for the direction of travel being protected.
From a system designer point of view, this means that the type of B1 and B2 devices must match the brand of operator included in the system design. (More on B1 and B2 devices later in this chapter).
Exception: Emergency access controls only accessible by authorized personnel (e.g., fire, police, EMS) may override entrapment protection means.
UL created a table, 32.1, showing the entrapment device selections that may be used, listed by Type of Gate and Type of Operator.
The operator manufacturer may provide the Type A entrapment protection device built into the machine. This typically will count as one entrapment device in each direction of travel.
The manufacturer recommends the additional device(s), but it is the system designer or
installer’s decision to determine the second entrapment protection device to use.
The two independent entrapment protection means must be independent of each other. The same type of device may not be used to meet the requirement for two means of protection.
Some operators are specifically designed and manufactured to meet Class 3 and/or 4 installs ONLY. The system designer and installer should recognize that the operator being specified/installed meets the class of installation.
Operators listed for Class 3 or 4 installations only, cannot be installed on Class 1 or 2 applications.
ENTRAPMENT – The condition when an object is caught or held in a position that increases the risk of injury.
Locations between a moving gate and a counter opposing edge, or surface where entrapment is possible up to 6 feet above grade.
Such locations occur if during any point in travel the gap between a moving gate and fixed counter
opposing edges or surfaces is less than 16 inches.
Drawing 5-2221
Locations between a moving gate or moving, exposed operator components and a counter opposing edge or surface where entrapment is possible up to 6 ft above grade.
Such locations occur if during any point in travel:
The gap between the bottom of a moving gate and the ground is greater than 4” and less than 16”; Exception: For a horizontal swing gate operator, at least two independent entrapment protection means are required in each direction of travel.
If there is no entrapment zone in one direction, only one means of protection is required in that direction.
The other direction must have a minimum of two means of protection.
a) The gap between the bottom of a moving gate and the ground is greater than 4” and less than 16”, or
b) The distance between the center line of the pivot (hinge) and the end of the wall, pillar, or column to which it is mounted when in the open or closed position exceeds 4 in.
c) Any other gap between a moving gate and fixed counter opposing edges or surfaces or other fixed objects is less than 16 inches (examples are walls, curbs, berms, or other immovable objects).
Locations between a moving gate or exposed operator components and a counter opposing edge or surface where entrapment is possible.
Such locations occur when the gap between a moving gate and fixed counter opposing edges or surfaces, other than the ground or floor at the bottom of the gate, is greater than 2.25 in and less than 16 in on the public side of the gate, or on the private side of the gate is greater than 4 in and less than 16 in, or when the gap between a moving gate and fixed counter opposing edges or surfaces at the bottom of the gate is less than 16 in.
Locations between a moving gate or exposed operator components and a counter opposing edge or surface where entrapment is possible up to 8 ft above grade.
Such locations occur when the gap between a moving gate and fixed counter opposing edges or surfaces, other than the ground or floor at the bottom of the gate, is greater than 4 in and less than 16 in or when the gap between a moving gate and fixed counter opposing edges or surfaces at the bottom of the gate is less than 16 inches.
· All UL 325 listed gate operators must have a minimum of two independent entrapment protection means in each direction of travel.
Exception: For a horizontal swing gate operator, at least two independent entrapment protection means are required in each direction of travel. Except, if there is no entrapment zone in one direction of travel, only one means of entrapment protection is required in that direction of travel; however, the other direction must have two independent entrapment protection means.
The installer is responsible for ensuring that all necessary devices are supplied andinstalled according to the gate operator manufacturer’s instructions.
· Type B1 or Type B2 means, shall be monitored for the presence of the device, including the wiring to it, at least once during each open and close cycle of operation.
Under some entrapment conditions the operator may go into either a soft shutdown or hard shutdown (alarm) condition. To determine what type of reset action is required, the installer should understand how the different entrapment conditions affect the gate operator.
These occur in situations where the inherent or external safety devices have been activated.
Soft shutdown condition – The operator will stop or stop and reverse a minimum of 2” depending upon the type of device that initiated the soft shutdown. The operator will not respond to any input that was present when the entrapment protection device sensed an obstruction. In some conditions, a soft shutdown may reset as soon as the entrapment condition clears (B1 device during opening cycle).
When the operator is in a soft shutdown, activation of any intended input will reset the operator. An intended input includes any command, any standard safety input, and any loop input. Activating any of these inputs will reset the gate. At that point, the gate will return to normal operation. If the gate is open, the automatic close timer will then time out and close the gate.
Hard shutdown (alarm condition) – The inherent entrapment protection system (Type A) has sensed two consecutive obstructions before the gate reaches the fully open or closed position or without receiving a gate command.
In a hard shutdown condition, the only way to reset the gate operator and return it to normal operation is to activate the alarm reset input or to cycle the power. Once the gate has been reset, an open or close command is needed to start the gate operator.
All the various types of entrapment protection means are identified in the standard. If the industry develops new types of entrapment protection means, these means will be placed into one of these categories. Some entrapment protection means are authorized only for certain types of gates as shown in the standard.
The UL325 standard defines the types of entrapment protection means in the following manner:
· Type A – Inherent entrapment protection system.
· Type B1 – Non-contact sensor (Photoelectric sensor or the equivalent).
· Type B2 – Contact sensor (Edge device or the equivalent).
· Type C – Inherent force limiting, inherent adjustable clutch or inherent pressure relief device. Note: UL 325 permits these only in swing gates and barrier arms.
· Type D – Actuating device requiring continuous pressure to maintain opening or closing motion of the gate, within line of sight of the gate.
The Type A device is provided by the manufacturer. There are multiple forms of inherent entrapment means.
Force sensors, RPM sensors and position sensors are some examples. Regardless of the means provided, the gate operator must be adjusted by the installer according to the manufacturer’s installation instructions.
The Type B1 device is typically a photo-reflective or a through-beam sensor. Manufacturers test their gate operators with specific brands of B1 devices and will list acceptable devices in their manuals.
Drawing 1-2108
The Type B2 device is typically a gate edge sensor. This may be used in conjunction with an edge transmitter and receiver when mounted on the moving gate panel. Manufacturers test their gate operators with specific brands of B2 devices and will list acceptable devices in their manuals.
Drawings 1-2108, 2-2109 and EZ-1 show some common sensor placements.
It is the system designer’s responsibility to determine the proper number and mounting locations of these devices to minimize the risk of entrapment and comply with UL 325. This training guide provides a general guide for what is considered common industry practice for the installation of these entrapment protection devices. In many systems there may be a mixture of devices needed to meet the needs for entrapment protection.
Drawing 2-2109
Drawing EZ-1
Always refer to the manufacturer’s instructions for recommendations and specific operator requirements on entrapment devices. Mounting placement and dimensions shown in drawings are not part of the UL 325 standard.
A clutch, a pressure relief device or an inherent force limiting means can never be used for an entrapment protection means on a horizontal slide, vertical lift, or vertical pivot regardless of the class of the application.
The manufacturer must identify that the clutch or pressure relief is defined as a Type C device. The Type C means may only be used in a swing gate or a barrier arm.
If there is a provision for the connection of an actuating device requiring continuous pressure to maintain opening and closing motion of the gate, that device must be located at least six (6) feet from the gate and within line of sight of the gate system.
The Type D means must also have the required instruction warning placard per UL 325. That placard should read:
″WARNING″ and the following statement or the equivalent:
″Moving Gate Has the Potential of Inflicting Injury or Death – Do Not Start Gate Unless Path is
Clear″
A gate operator installed utilizing entrapment protection designated Type A, shall upon sensing an obstruction in any direction:
· Stop and initiate the reversal of the gate within 2 seconds. The gate operator shall reverse the gate a minimum of 2 inches. The gate operator shall enter a soft-shutdown condition.
· Stop the gate upon sensing a second sequential obstruction before reaching a limit position or before receiving gate command. The gate operator shall enter a hard- shutdown (alarm) condition.
A gate operator using a Type B1 entrapment protection means, shall, upon sensing an obstruction in the direction of travel of the gate:
· Stop or reverse the gate within 2 seconds.
· If the gate is reversed, a 2nd obstruction would stop the gate.
· Result in a gate at rest remaining at rest. A Type D device may be used to move the gate.
· Once the obstruction to the sensor is cleared, the gate shall return to normal operation.
A gate operator using a Type B2 entrapment protection means, shall, upon sensing an obstruction in the direction of travel of the gate:
· Stop and reverse the gate within 2 seconds and reverse the gate a minimum of 2 inches.
· Upon sensing a 2nd obstruction, stop the gate and go into a soft shutdown.
· Results in a gate at rest remaining at rest. A Type D device may be used to move the gate.
· After the sensor is actuated no more than 2 times while closing without having reached the close limit device, or once in a single opening cycle, the gate shall enter a soft- shutdown condition.
EDITORS NOTE: The reversing of the gate upon obstruction sensing takes place during both opening and closing of the gate cycle and is not limited to just the closing part of the cycle.
The level of safety must consider the site application and must meet a balance of both safety and security. The UL325 standard defines four classes of gate usages.
It is the designer’s and the installer’s job to match the site application to the appropriate class of gate and ensure the gate operator to be installed is rated for that class of gate. Operator manufacturers will state the class of each operator in multiple places, on their machines and installation manuals.
The correct class of operator for the site application should be determined by the salesperson/designer during the sales process. It remains the responsibility of the installer to ensure the proper class of operator and the two independent entrapment protection devices match the site application.
· Class I Residential Vehicular Gate Operator - A vehicular gate operator (or system) intended for use in garages or parking areas associated with a residence of one to four single families.
· Class II Commercial/General Access Vehicular Gate Operator - A vehicular gate operator (or system) intended for use in a commercial location or building such as a multi- family housing unit (five or more single family units), hotel, garages, retail store or other buildings accessible by or servicing the general public.
· Class Ill Industrial/Limited Access Vehicular Gate Operator - A vehicular gate operator (or system) intended for use in an industrial location or building such as a factory or loading dock area or other locations not accessible by or intended to service the general public.
· Class IV Restricted Access Vehicular Gate Operator - A vehicular gate operator (or system) intended for use in a guarded industrial location or building such as an airport security area or other restricted access locations not servicing the general public, in which unauthorized access is prevented via supervision by security personnel.
See drawings below.
Drawing 3-2009
Drawing 4-2203
Drawing 5-2221
Drawing 57-2303
Drawing 59-2302
Drawing 6-2403
Drawing 172-2404
Drawing 7-2005
A minimum of two warning signs, or placards, shall be installed, in the area of the gate and be visible by persons located on either side of the gate. It is generally recommended that installers take a photograph of the warning signs to document that the signs were installed and place the photographs in the permanent job file.
Drawing 6-2008.
Note: these instructions must be included in the operator manual. Some of these may also be covered under the ASTM F2200 Standard:
Install the gate operator only when:
· The operator is appropriate for the construction of the gate and the usage class of the gate.
· All openings of a horizontal slide gate are guarded or screened from the bottom of the gate to a minimum of 6 ft above the ground to prevent a 2-1/4” diameter sphere from passing through the openings anywhere in the gate, and in that portion of the adjacent fence that the gate covers in the open position.
· All areas of the moving vertical pivot gate panel from the bottom of the gate to the top of the gate or a minimum of 72 in above grade, whichever is less, that pass by a fixed stationary object, and in the area of the adjacent fence that the gate covers during the travel of the gate, shall be designed, guarded or screened to prevent a 2-1/4 in diameter sphere from passing through.
· All exposed pinch points are eliminated or guarded, and
· Guarding is supplied for exposed rollers.
· The operator instructions shall list the maximum number of open and close entrapment protection devices capable of being connected to the operator.
· The operator is intended for installation only on gates used for vehicles. Pedestrians must be supplied with a separate access opening. The pedestrian access shall be in a location so that a pedestrian will not be able to contact a moving vehicular access gate during the entire path of travel of the vehicular gate. A pedestrian gate shall not be incorporated into an automated vehicular gate panel.
· The gate must be installed in a location so that enough clearance is supplied between the gate and adjacent structures when opening and closing to reduce the risk of entrapment. Swinging gates shall not open into public access areas.
· The gate must be installed and work freely in both directions prior to the installation of the gate operator. Do not over-tighten the operator clutch or pressure relief valve to compensate for an improperly installed, improperly functioning, or damaged gate.
· For gate operators using Type D protection:
· The gate operator controls must be placed so that the user has full view of the gate area when the gate is moving,
· The placard as required by 62.1.6 shall be placed adjacent to the controls,
· An automatic closing device (such as a timer, loop sensor, or similar device) shall not be employed, and
· No other activation device shall be connected.
· Permanently mounted controls intended for user activation must be located at least 6ft away from any moving part of the gate and where the user is prevented from reaching over, under, around or through the gate to operate the controls.
· Exception: Emergency access controls only accessible by authorized personnel (e.g., fire, police, EMS) may be placed at any location in the line-of-sight of the gate.
· The Stop and/or Reset button must be in the line-of-sight of the gate. Activation of the reset control shall not cause the operator to start.
· A minimum of two (2) WARNING SIGNS shall be installed, in the area of the gate. Each placard is to be visible by persons located on the side of the gate on which the placard is installed.
Drawing 9-2101
Drawing 10-2301
Drawing 11-2402
Drawing 18-2103
Drawing 171-2601
Drawing 12-2006
· Understand the basics of electricity, including current, voltage, resistance, and power, and identify different types of electrical circuits in gate systems.
· Recognize various electrical components in gate automation, select the right materials, and learn proper techniques for handling and installing them.
· Learn the importance of proper wiring and cabling in gate systems, know the different types of wires and cables, and apply safe and efficient wiring techniques.
· Understand safety measures for working with electrical systems, including grounding and bonding, troubleshoot issues, and use tools like multimeters for maintenance.
This chapter will start by reviewing some common electrical concepts that affect gate operator systems. A system designer should be familiar with what type of wire & what size wire is required for all the equipment being used on a project. The designer may be required to specify what is needed so the electrical contractor knows what to supply. When adding equipment that may be new or not common in the company, tell the company technicians what the new wiring requirements are.
Not only is it the job of the designer to design a system that meets the feature and performance needs of the customer, but it is also the designer’s job to design a system that is as safe and reliable as possible. Knowledge of the electrical requirements of the items on the project is crucial to the project's success.
Electricity is defined as the flow of free electrons. Free electrons are negatively charged elements of an atom that can leave the atom under the right conditions. Electricity flows through a conductor or wire by the movement of these free electrons. This flow of free electrons is called current. The quantity of the electrons, or current, flowing past a point in time is measured in units called amperes, or amps for short.
As a system designer, it is important for to understand some basic electrical concepts and how those concepts may affect the design of the gate system. Depending on the system parameters, this can affect the type of gate operator used. This may also pertain to the type of controls and accessories, along with the conduit runs for the system, and many other factors in the system design. This chapter is intended to provide a general overview on electrical considerations for gate systems. Refer to equipment manufacturers instructions for more details, and discuss with these with the installation team, and/or electrician.
Amperage is the flow of electricity through a wire. This must be controlled to protect the electrical wires from overheating or short-circuiting. This is done by matching the load demand to the wire size and must be protected using fuses or circuit breakers.
Motors, accessories, and other devices that use electricity are rated as to the maximum amperage they could require, such as a vehicle detector at .1 amps or a gate operator at 13 amps. A common term for the amperage a device uses when running is its amperage draw or current draw. This may be shortened to just draw.
Amperage also becomes an important factor
when using either solar or battery powered gate operators where the installer
needs to match the current demand to the battery or solar panel capacity.
A motor that is overloaded by moving a stiff gate may draw as much as 130% times its FLA without great concern. However, motors may also draw up to 3 times their FLA current rating in the first
ľ second after starting. This must be considered in making calculations for the gauge of wire and distance to power source.
Accessories and controls also are measured in how much power they require to function. Typically, low voltage accessories are measured in Milliamps, which is one thousandth of an Amp. (1 mA = 0.001A
Understanding how much current draw is required factors into wire size, and voltage selection for operators, controls, and accessories.
Wiring is a significant factor in the performance and reliable operation of gate and access systems. Good wiring practices make life much easier for a technician in the field. And this starts with the design and layout of the system.
·
Understand the different
types of wire and cable available, and what to use when wiring the total
system.
·
Following color codes is essential.
·
Every
piece of equipment in a gate or access system has wiring connections. Even “wireless” devices have wiring to the actual equipment
at both ends of the connection. Understanding the differences in wire and cable and using good wiring
technique can make installations go smoothly and efficiently and can really
affect the ease of service down the road.
There are several factors to consider when specifying wire and cable for a system.
·
Wire Size
·
Solid vs Stranded
·
Type of wire insulation
·
Single conductor
vs Multi Conductor cable
·
Multi Conductor vs Multi Pair
cable
·
Color Codes
Always refer to the equipment manufacturers manual. This will specify what size and type of wire or cable to use with their equipment.
Wire size affects the flow of electricity between the source and the device or equipment being connected. The smaller the wire is, the more resistance it has. There is less copper for the electricity to flow through.
Likewise, the longer the wire run is, the more resistance there is. The electricity is moving through more copper from point A to point B. Small wire size and/or long wire runs can reduce the usable voltage at the end of a long run.
For example, the long electrical distance between a power panel box and the gate operator will create a significant resistance from the wire alone. This can result in voltage drop at the gate operator when it is using a peak load.
Electrical wire is identified by wire size using a number scale from 00 up to 26. The lower number indicates a larger diameter wire. A chart that shows a #12-gauge wire is required means that a #12 or lower gauge meets, or exceeds, this requirement.
For primary power to an electrical device, a #12-gauge is the minimum allowed by the National Electrical Code. Internal wiring within a control panel may use a smaller gauge wire, but nothing smaller than #12 is acceptable as the primary power feed.
·
18 awg wire is smaller than 16
awg wire.
·
12 awg is smaller than 10 awg.
·
Typical wire size for electrical supply voltage is 10 awg or 12 awg.
·
Typical wire size for accessory or low voltage connections is 18 awg.
·
Access controls may use multiple conductor or twisted pair
wiring. Depending upon the type of
device being used, wire sizes may be 20-24 awg.
Wire comes either with a single solid conductor inside the insulation, or a conductor consisting of multiple strands of wire.
These are used for
different types of electrical connections. Depending
on the type of device being connected, these maybe or may not be interchangeable.
Solid conductor is usually found in supply voltage wiring or other high voltage connections. In larger gauges, this provides a strong, lower resistance pipeline for the power feed.
Solid conductor is also used in communication wire to provide a cleaner signal. For example,
telephone wire and Ethernet cables are typically solid conductors. In
smaller gauges, solid conductor can be brittle and easy to break. Cat5 cable,
for example.
Stranded conductor is often found in control wiring and in low voltage connections. Stranded wire is easier to pull through conduits and is less likely to break while making connections to terminal blocks.
Stranded wire provides better connections in terminal blocks when multiple wires are inserted into the same terminal position. This is also easier to get a good connection with crimp on connectors.
This is a single wire with insulation protecting a single conductor. Typically used for making individual connections inside equipment, or for supply voltage wiring to a gate system.
However, this may be difficult to work with when interconnecting different equipment in a gate system. Also, pulling multiple “single conductor” wires through conduit can be challenging.
This is providing multiple wires inside an overall protective jacket. Multi-conductor cable can be found in many combinations:
·
2-conductor
is often used for low voltage power wire or relay wiring.
·
4-conductor,
for running low voltage power and relay in the same cable.
·
6 or
8-conductor, for wiring multiple devices in the same overall cable. It never
hurts to have spare conductors available!
Different from multi-conductor cable, multi- pair cable has the internal wires separated into matching pairs. These may be color coded in pairs, such as Green/White and White/Green, or may be paired with a common color for one side of the pair, for example Blue and White, Red and White, Orange and White.
The pairs may also be twisted together. This is typically found in communication wire, such as telephone wiring or Ethernet cable.
Twisting the pairs together allows for any outside interference or influence to affect both wires equally, reducing the potential for noise in the wiring in some cases.
Some multi-conductor or multi-pair cables are shielded. This consists of an aluminum or braided shield and often includes a drain wire for connecting to ground.
In some cables, each individual pair has its own shield. Shielded cables should be grounded at one end of the cable and the shield should be floated at the other end of the cable.
Typically, the grounding will occur at the home control panel or primary equipment location.
Each of these wire and cable types are used in different applications and for different types of connections. In many cases, using the wrong type of wire can lead to functional and operational problems that can affect the equipment.
For example:
·
Telephone
wire should be twisted pair without a shield.
Using non-twisted wire or using shielded cable can induce noise into the
telephone line.
·
Wiegand card reader wiring
should be multi-conductor cable with an overall shield.
Using twisted pair wiring can reduce the length of usable wire run and
can cause intermittent communication errors with the operation of the Wiegand
device.
·
If
multiple solid conductor wires are inserted into a terminal block, all wires
may not get a good electrical connection within the terminal
block. Some may end up being loose inside
the terminal and provide intermittent problems with the system performance.
Any wiring between equipment should be run through a protective conduit. Conduit is a pipe or tube through which the wire is run to protect it from mechanical or environmental damage.
Conduit may be made of metal or plastic but is most commonly a non- ferrous material in outdoor applications to reduce damage from rust. One advantage of using conduit when wire is going to be run underground is to make replacing the wire easier should it get damaged.
Using the correct
type of wire or cable
insulation is important!
PVC insulation: A common type of insulation on single wires and for jacketing material on multi-conductor cable. This is a soft insulation that provides protection for the internal wires. PVC is does not have good resistance to moisture and can become saturated when immersed in water (such as conduits filled with water).
Waterproof insulation: This typically is a jacketing material that provides better protection against moisture contamination. Waterproof cables often have some additional protection inside, such as gel fill surrounding the internal conductors. Sometimes this is referred to as “direct burial cable”.
TFFN, THHN insulation: This is a combination of PVC insulation on wires with an additional coating to provide additional protection. The coating may be nylon or some other material. This can provide a level of protection for gasoline and oil resistance, and some protection against moisture contamination.
XLPE insulation: This is “cross linked polyethylene, used primarily for in-ground loop wiring. It provides a high level of moisture and abrasion resistance.
Plenum Cable: Special jacketing or insulation for wiring going into “return
air plenum” areas in
the ceiling space of buildings. These withstand high heat, and do not give off poisonous fumes when burned. If “plenum” wiring is required, and standard wiring is
installed, the fire marshal may red tag the installation and require all new
wiring be pulled.
The National Electrical Manufacturers Association (NEMA) has a rating system for electrical enclosures and the applications for which are appropriate. In most cases the manufacturer will have already selected an enclosure with the necessary rating for their operator, but if an extra enclosure is needed, it is important to learn and follow these ratings.
The most common enclosures used in the gate operator industry are:
NEMA Type 1: Enclosures intended for indoor use primarily to provide a degree of protection against contact with the enclosed equipment or locations where unusual service conditions do not exist.
NEMA Type 3R: Enclosures intended for outdoor use primarily to provide
a degree of protection ag
ainst falling rain and snow; undamaged by the formation of ice on the enclosure.
NEMA Type 4: Enclosures intended for indoor or outdoor use primarily to provide a degree of protection against windblown dust and rain, splashing water, and hose directed water; undamaged by the formation of ice on the enclosure.
NEMA Type 4X: Enclosures intended for indoor or outdoor use primarily to provide a degree of protection against corrosion, windblown dust, and rain, splashing water, and hose directed water; undamaged by the formation of ice on the enclosure.
NEMA Type 9: Enclosures are intended for hazardous locations. Hazardous
locations are described by the class and division of the hazard,
which is information that must be provided
before compatibility of an enclosure can be known. Some industries occasionally
publish a specification for an explosion proof gate operator. This should be
coordinated with the manufacturer of the gate operator to ensure such an
operator is available. Use the gate operator manufacturer’s expertise to
coordinate this specification.
AC voltage is common for residential and commercial areas. Most residential properties will have 115V and 230V single phase power available. In commercial or industrial locations, higher voltages and three-phase power may be found. Selection of power to use for a gate system may depend upon several factors, including:
·
Distance of supply voltage
wire run from electrical panel
to the gate system.
·
Size and weight of the gate, and type of operator
used.
·
HP of the operator
Alternating current reverses the direction of flow between the positive and negative 60 times per second (60Hz) in the U.S. One complete period, with current flow in one direction and then in the other is called a cycle.
The cycles are called Hertz, thus the AC power in the U.S. is best stated as being 60 Hertz. The number of cycles per second is also called a frequency.
AC voltage can be produced in single phase or three phase power: In this study guide, the term 115 volts is to be taken as being the same as 110 volts or 120 volts.
Likewise, when this study guide states the term 230 volts, that is to be taken as the same as 220 or 240 volts, and 460 volts is the same as 440 or 480 volts. These slight voltage differences are not a factor regarding acceptable voltages. However, 208 volts is a separate voltage category from 230 volts.
Single Phase: Single phase power consists of a single 60Hz cycle of electrical. This would be a hot wire and a negative wire for 115V, or 2 hot wires for 208 or 230V. Residential sites are provided with both 115-volt and 230-volt, single phase power in the home. It would be rare to find three phase power at a residence.
Three Phase: Three phase power consists of 3 hot wires working
together. This provides 3 overlapping power cycles, each providing 60HZ but
offset from each other. This is
intended for heavy duty/high horsepower motors and is a better voltage for gate
operators on large or heavy gates.
Three phase power is
available in 208V, 230V, 460V and 575V (Canada). Anticipate that
commercial/industrial applications may have single phase and three phase power available, and often different voltages
available.
The available supply voltage power is more constant in a three-phase system than in a single- phase system. This results in smoother operation, less vibration of motors and other AC devices. Three phase motors and generators are more economical to run than single-phase machines.
There are many gate
operators, typically residential and commercial units, that are designed to
operate only on 115 volts.
These operators use low amperage
motors and are designed for gates
usually weighing up to 1000 or 1500 pounds depending upon the motor horsepower.
Even with these
operators, the installer should be aware of the potential for a voltage drop,
especially if the operator is a
long distance from the power
source. Gate operator
manufacturers may also have operator models
available with dual voltage motors
which will accept either 208 or
230 volts without a problem.
The installer may
have to change the wiring in the operator to ensure the system is getting the
correct secondary voltage.
208 or 230 volts are the only voltages that can be either single
or three- phase. The installer
must determine which will be provided for the gate operator power.
Gate operators may
have the option to be changed on site between 115- and 230-volt single phase; and the same for 230 and 460-volt
three-phase. It is not possible
to change a gate operator between single and three-phase
without changing the electric motor, and probably the control panel. This is
dependent upon the actual make and model of gate operator.
It is important to know the “true electrical distance” of the supply voltage wire. What is the actual length of wire in the conduit between the electrical panel and the operator? This is based upon how the conduit is routed at the site.
It is important to know that the more current (amperage) a device draws, the larger size wire is required to supply electricity to the device. However, this is also affected by the voltage being supplied.
·
As current
draw goes up, wire must be larger.
·
As supply
voltage goes up, wire sizes are reduced.
The gate operator
manufacturer provides a wire chart in the installation manual
with requirements for wiring
distances. They have calculated the
demands of the operator, controls, and accessories.
This wire chart should be provided to the electrician and insist he follow the charts as a minimum for the electrical wiring provide to the operator. There should be a dedicated circuit for each gate operator.
If a wire chart requires 12 awg, use 12 awg or larger (10 awg for example). However, make sure the terminal connections in the operator or accessories will work with the wire size being used.
Examples
of these wire charts are on the following page.
This designation refers to the amount of allowable voltage and insulation requirements for wiring electrical devices. Class 1 circuits allow for higher voltage but require better insulation and some type of power limiting device such as a circuit breaker or fuse.
Class 2 and 3 circuits
are lower voltage applications with limitations on how much current can be
supplied. Class 3 can carry more current than Class 2 but less than a Class 1
circuit.
Class 2 or low voltage wiring may involve a different electrical licensing depending on the city or state where the work is being performed. Some areas have separate low voltage licensing.
Some areas require a full electrical license to work with low voltage. Always understand the regulations that apply for the jobsite.
A Class 2 circuit is defined as an isolated secondary circuit involving a potential of not more than 30 volts (42.4 volts peak) supplied by:
A. An inherently limited Class 2 transformer of less than 100VA.
B. A combination of an isolated transformer secondary winding and a fixed impedance or regulating network that together comply with the performance requirements for an inherently limited Class 2 transformer.
C. A dry-cell battery having output characteristics not greater than those of an inherently limited Class 2 transformer.
· Any combination of a, b, and c above that together comply with the performance requirements for an inherently limited Class 2 transformer.
·
· One or more combinations of a Class 2 transformer and an over current protective device that together comply with the performance requirements for a non-inherently limited Class 2 transformer.
In gate systems, most of the control wiring and accessories are considered Class 2 circuits:
·
12VAC/12VDC, power from control
boards and power
supplies
·
16.5VAC, power supplies for
accessories
·
24VAC/24VDC, power from control
boards and power
supplies
·
Gate Operator
Commands from controls
to the operator circuit board
DC voltage (direct current) is electricity flowing continuously through a conductor in only one direction. Direct current can be chemically produced by a battery.
Electrons flow from the negative battery terminal through the conductor, to the positive battery terminal, completing the path. DC motors can vary speed based on input voltage. This enables an operator to start and stop softly, imparting less stress on the gate system.
Drawing 173-5014
DC Operators have increased in popularity over the past several years. These offer the benefit of providing gate operation when supply voltage is lost. They also may provide the added function of Slow Start/Slow Stop to the operator cycle.
Operators referred
to as DC operators typically
use one of the four following methods:
1. AC source power is converted to DC power, which then provides the power to run the motor. Batteries are only used if the AC source power is lost and as such the operator will remain operational even with the batteries removed.
2. AC source power is converted to DC power, which provides some of the power for the DC motor. Batteries provide the remainder of the power.
3. AC source power is used to recharge batteries only. Batteries must be in the circuit otherwise the motor will not run.
4. Solar panel power is used to recharge batteries only. Batteries must be in the circuit otherwise the motor will not run.
One advantage that DC operators provide is the ability to run supply voltage farther on smaller wires. This is due to the batteries providing much of the power needed to run the motor. An example of a wire chart for a DC operator:
Lead acid batteries
commonly put out 12 to 14 VDC (volts DC). A 24-volt system requires two such batteries
run in series. The advantage
to the higher voltage is a reduction in system current to produce the same power but
more space must be considered for the two batteries and there will be more
components that will need service and replacement over time.
12 VDC systems are often used in solar applications because single 12v panels are
less expensive and easier
to mount than 24v panels or dual 12v panels.
The number one problem with any battery powered system is getting
a good battery and then keeping that battery charged. Batteries have a finite
life, especially in extreme environments.
A battery is a device that converts chemical energy into electrical energy. There are various types of batteries, but most gate operators use either sealed lead acid (AGM) or gel cell batteries. These are sealed batteries to reduce maintenance.
While these batteries can be recharged, they will deteriorate over time and eventually need to be replaced. An advantage of this type of
battery is the ability to withstand greater temperature variation than other
batteries.
A misconception about batteries is that they store whatever charge is given to them, and rarely ever considered from the view that it is a component of an electrical system much like any other component. Different types of batteries have different optimum charging voltages and currents.
It is important not to put any other of battery than the type of battery specified by the manufacturer for use in their operator. Referring to a typical lead-acid battery, it is designed to operate between
1.75V/cell to 2.1V/cell, which for a 12V battery is 10.5Vdc to 12.6Vdc. The number of times a battery can be charged and discharged depends predominantly on the number of times the battery has been discharged to below 1.75V/cell.
All batteries use capacity curves and life cycle curves that are dependent on the depth of discharge. For this typical battery example, the battery may have a life of 2000 charge/discharge cycles if it is never discharged to less than 50% capacity. The same battery will reduce its life to
less than 1000
cycles, if even ONE occurrence of a discharge to less than 1.75V/cell level and
less than 100 cycles if it was ever discharged to 0 volt.
This is a common question related to DC gate operators. There are many factors that affect this. Here are some of these factors:
Amp-Hour (ampere-hour, Ah) is a way of describing a battery’s capacity - how long it will run before it is drained down. More specifically, the amp-hour rating for a given battery is the maximum amperage that can be drawn continuously until the battery is completely discharged over a specific time.
The battery is the gas tank, the amp-hours is how much gas is in the tank. Battery manufacturers complete tests on their batteries to give them an amp-hour rating. A typical time for a test is 20 hours.
Example calculation: Take a 100 amp-hour battery, tested over a 20-hour period. 100 amp-hours divided by 20 hours = 5 amps. That means that the battery manufacturer claims the battery can sustain a 5-amp load for 20 hours until the battery is completely dead.
That is great, but now, put it into realistic terms. To begin, a battery should never be drawn to a completely flat, empty, dead state as it will significantly reduce the life of the battery. A good rule of thumb (battery type depending) is that a battery should only be drawn down to 40% of its original capacity, or in other words, 60% of the battery capacity can be used in day-to-day activity.
Getting back to the 100 Ah, 5-amp load example, the 20@ 5A rating, when factoring in the preferred limit on battery usage of 60%, is really 12 hours (20hr x 60%).
The other factor that affects how long a
gate will operate under battery power is how much power is used at any given time. The more amperage drawn, the lower
the battery capacity.
Just like driving a car, going faster reduces the MPG. Drawing amps faster reduces the amps available for use. This is referred to as Peukert’s Law.
Peukert’s law was presented by German scientist W. Peukert in 1897. Simply stated, the true
capacity of a battery is dependent on the rate of discharge.
The faster the rate of discharge (drawing more amps), the less total Ah capacity can be delivered. For example, a battery might be rated at 100 Ah when discharged at 20-hour rating of 5A.
However, if the battery is discharged at a higher load, say 10A, the battery capacity will be shortened. When using at a higher load there will only be 90% of the battery capacity available.
An easy way to understand Peukert’s law is to look at a glass of beer. Yep – beer. Beer and amp hours have a lot more in common than people may think. When the beer is poured quickly into the center of a glass, there will be a small amount of beer at the bottom and a lot of foam at the top. Pour the same beer slowly down the side of the glass and there will be lots of beer in the glass and a small amount of foam at the top.
The liquid in the glass represents the capacity available for use. The faster the pour the less capacity available. If the beer is poured slowly, there is more beer to drink.
Back to the numbers…Using the 100 Ah battery at 5 amps draw gives 20 hours of battery life.
Then factoring in the 60% rule = 12 hours.
Now, take the same battery and factor in Peukert’s law. Using the 100 Ah battery at 10 amps draw gives 10 hours of battery life. Factor in the 60% to maintain battery life and we have 6 hours.
Now, reduce this
again because of the higher current draw (Peukert’s
law). 6 hours x 90% = 5.4 hours of battery
life, which is quite a difference from the 10 hours that was expected, or the 100AH that was thought that a 100AH
battery may have.
Batteries are temperature sensitive. Different temperatures affect the internal chemical reaction rates and internal resistance and efficiency of all types of batteries.
Batteries like to live at 77 F. Anything below this, batteries start to lose efficiency, but their life can be extended. Anything above this and battery life decreases, but their efficiency increases.
RUN TIME (efficiency): INCREASES as the temperature rises above 77°F and DECREASES as the temperature fall below 77°F.
BATTERY LIFE: Will DECREASE as the temperature rises
above 77°F and INCREASES
as the temperature falls below 77°F.
Solar charged systems can, if designed properly, support a full complement of accessories. Accessories that are to be powered by the gate operator battery should be solar friendly when possible to prevent having to install large and expensive solar panels.
There are two major components to a solar friendly accessory, current consumption, and the minimum operating voltage:
Solar friendly accessories are designed by the manufacturer to operate on a low current typically 1 milliamp (.001 amps) or less. This is referred to as the standby current or current consumption of the device.
The other factor to consider is the minimum operating voltage of the accessory. Some accessories are designed to operate at a minimum voltage of 12 VDC and will not perform correctly at voltages below 12 VDC.
For a solar powered system, accessories with a minimum operating voltage of 10VDC or lower is desired to avoid intermittent operation of the accessory.
Maintaining proper charge of the batteries is critical to keep reliable operation of the gate system. DC operators control the charge from the AC supply voltage to maintain the DC batteries.
Some operators also monitor battery status and will offer the option of shutting down when batteries reach the recommended discharge rate, rather than running the batteries completely dead.
On solar operators, many manufacturers include a charging controller, which is designed to monitor charging of the batteries and protect the batteries from over-charging. Operator manufacturers often provide charging sufficient for the operator and standard controls.
However, in solar gate systems, and even DC systems with AC charging, there are often added accessories and controls which can affect the battery discharge rate and the charging requirements.
If the battery does not have sufficient
charging capacity, it can walk down in the charge level, eventually reaching
a discharge state
that cannot be recovered from during the daytime charging cycle.
If powering the entire system from battery power, and using solar to charge, there may be a need to develop a more comprehensive solar package, matching battery size and charging capacity with the expected load of the operator, controls, and accessories.
The solar charging system is the solar panel, solar charge controller and the batteries. Selecting the proper solar charging system can depend on many environmental and system factors.
· The number of cycles expected per day
· Accessories that will be required
· Required accessories and their amp draw
· Geographic location
· Amount of sunlight per day
· Impact from shade
· Size of the gate
· Distance of the panel from the operator
The system must be designed to properly charge the battery, prevent premature battery drain and maximize battery life. Some colder climates may prevent the usage of solar applications for gate operators.
Manufacturers and/or
distributors often provide instructions regarding the proper solar panel sizing
and battery usage for their equipment. When adding accessories, consult with
the manufacturer, or consider operating the accessories from a separate power
source.
To calculate the correct solar panel size needed, the Total System Current Draw per Day of amps to operate the system (TSCDD) must be determined. There are several different factors needed to determine to get the TSCDD.
· Current Consumption of the Gate Operator at Idle: CCGO Idle
· Current Consumption of the Gate Operator while operating: CCGO operating.
· Current Consumption of Accessories multiplied by 24 hours per day: CCACC x 24 =Z
Look at each of these factors:
Current
Consumption of the Gate Operator
at Idle: CCGO
Idle x 24 hours per day = X
If the gate operator and control board draw 10 milli-amps at Idle (rest) then that multiplied this by 24 (hours in a day) and get 240 milli-amps. Divide this by1000 to get the Amp draw:
· 10mA x 24 = 240mA, / 1000 = .24Amps
Current Consumption of the Gate Operator
while operating:
CCGO operating x cycle time x cycles
per day =Y
If the gate takes 30 seconds to cycle full open
and runs 10 cycles per day, then it will operate a total of 300 seconds
(5 minutes) per 24-hour period.
There are 60 minutes per hour so divide 60 (minutes in an hour)
by 5 (minutes of total run time per day) and get 1/12 of an hour of cycle time
(run time).
· If the operator motor draws 1 amp of power while in operation, then divide the 1 amp by 12 and get .083 amps.
Current Consumption of Accessories multiplied by24 hours per day: CCACC x 24 =Z
If all the
accessories (radio receivers, photo eyes, loop detectors, etc.) total 10
milli-amps then multiply that by 24 (hours in a day) and get 240 milli-amps,
then divide by 1000 and get the CCACC (Z) .24 amps.
Now the Total System
Current Draw per Day (TSCDD)
may be determined.
· CCGO Idle (.24) + CCGO Operating (.083) + CCACC (.24) = Total System Current Draw per Day (TSCDD) of .56 amps.
With the total system current draw calculated, it is now known the amount of current the solar charging system must provide each day to keep the battery charged. Typically, solar panels have a VMP of 17.2 DC volts of output at peak charging time or maximum solar radiation (PV) per day.
The following chart (Figure 11) is a general guide to the amount of current the solar charging system can provide in different parts of the country. The chart assumes the solar panel is generally facing south and has no obstructions which might shade any part of the panel throughout the day anytime of the year.
Use the solar PV map to determine the hours of solar radiation received at the job’s location. To not use this map and the information it provides will certainly affect gate system’s operational efficiency.
Figure 11
Note: Doubling
the size of the solar panel will double the output current available to charge
the batteries. However, the solar
charge controller will also need to be capable of handling the higher output
from the solar panels. Always check with the instructions and specifications of the
charging controller to make sure it can handle the load.
Now we need to determine the minimum wattage panel required to keep the battery charged for the site.
Total System Current Draw per Day (TSCDD) multiplied by VMP (17.2)
divided by PV per day for the job location.
If the installation is in the Southeast part of the country, the formula would be:
· .560 x 17.2 = 9.63 divided by 5 (lowest number for zone) = 1.9 watts needed each day to charge the battery.
Inductance is an electrical principle in which a voltage in one set of electrical windings is induced into another set of windings. This is the principle used in transformers.
A problem area created by inductance exists when the high voltage in one set of electrical wires induces an electromotive force in a secondary circuit that is nearby. Primary power lines running in the same conduit with low voltage control lines is a common source of inductance interference in gate operators.
Running primary power from a building to a gate operator through the same conduit as control lines is not recommended and may be a violation of local electrical codes.
Unintended inductance, while not sufficient to activate a control, can cause premature failures of relay coils and components on logic control boards. It may even produce false signals in logic boards that can activate controls.
High and Low voltage wiring should be run in separate conduits and must be separated by a
minimum of 18” on long conduit runs to minimize the potential for this inductive interference.
Electrical current is generated when electrons in the outer valence band of an atom become unstable. This happens when the atom is excited by heat or light or magnetism. The electrons jump from atom to atom trying to regain stability.
Going beneath the earth’s surface, an electrically stable point is eventually reached. How deep one must go varies based on soil topography, but the NEC (National Electrical Code) specifies a minimum depth of eight feet below grade.
When the metal
chassis of a gate operator is connected to earth ground, it provides a low
resistance path to ground for any external noise that reaches the operator.
Electrical noise can be generated from satellite transmissions, cell phone
transmission, arc welders, radio station broadcasts, and many other sources.
These noise sources
can interfere with the microprocessor controller on logic boards inside an
operator. Providing a good earth ground connection can protect the system from
such interference.
Surge suppressors attempt to protect the gate operator system from damage due to power surges and lightning strikes. There are different methods used to do this but one of the most common devices monitors input voltage and shunts that voltage to earth ground if it exceeds the rated voltage for the surge device.
This type of gas discharge suppression only works if there is a good connection to earth ground and if that connection is placed before the surge reaches the circuit board but not so far away from the system that an external surge can hit after the suppressor.
The following suggestions provide advice on how to maximize the protection afforded by a surge suppression device.
Grounding and surge suppression:
Follow proper
grounding protocols. If surge suppression is used, follow
guidelines for location
of surge devices and wiring to ground.
· Place surge suppressions at ground rod: If surge device has more than three feet of wire to ground rod it will be ineffective.
· Do not place surge device inside equipment being protected. The goal is to keep lightning away from equipment control board.
· Common Value of Ground: Whenever possible, tie all grounds together to form a common ground path for transient voltage spikes.
When designing an automated gate system, the designer should specify the electrical requirements for the system. This may cover many different factors and may vary depending upon who will be performing the electrical work. The design and specification should include the following information:
·
The manufacturer’s wiring gauge chart
with horsepower and voltage to be used.
·
A clear
statement that the primary power lines must be in a separate conduit than the
control line; and that these two may be in the same trench but must be
separated by a minimum of 18-inches
of soil, except the area entering the gate operator.
·
That both primary and control conduits
are not run under, or especially not laid parallel to any side of a vehicle detector
loop by a minimum distance of three feet.
·
Run all electrical wires in conduits, and have the conduits enter the gate operator per the
· manufacturer’s instructions.
·
Provide the operator manufacturer’s plan view drawing
showing the proper
location for conduits to enter the chassis relative
to the gate. This is important as the conduits
must be properly located before the concrete mounting slab is poured.
·
Type and size of conductors for each access
control device to be installed, in
·
accordance with the manufacturer’s instructions.
·
Understand the role, importance, and key parts of access control systems
in automated gates, and learn about the different types of access control
systems.
·
Recognize different types of access control devices like keypads, card
readers, and remote controls, understand their uses and benefits, and learn how
to install and program them.
·
Learn how to connect access control systems with various gate operators,
understand the wiring and communication, and fix common issues to keep them
working properly.
·
Set up security measures to protect access control systems from
tampering and unauthorized access, understand the need for regular maintenance,
and use best practices for troubleshooting and keeping them reliable.
This chapter offers insight into the access controls available today. Even as technology evolves, control devices tell the gate system what to do and when to do it. Selecting the right types of access for a system is based upon many different factors.
There may be multiple types of access devices for different groups of people that use the gate system. Consider the demographics of the residents or system users.
Discuss with the property owner the benefits of the different types of devices, and if the property owner may want to offer a “standard” form of access, and/or a more advanced form of access at an additional fee for residents.
If gate operators provide the muscle that move the gate, then controls & accessories would be considered the brains.
·
If the user wants the gate to open, something must tell the operator to open.
·
If the user wants the gate to
stop, something must tell the operator to stop.
·
If the
user wants the gate to reverse back open, something must tell the gate to
reverse back open.
This is the function
of controls and accessories.
In simple terms, every device will provide the following sequence
of functions:
Accessory and control devices are divided into several categories:
· Access Control Devices: These provide OPEN, CLOSE and HOLD commands to the gate operator.
· Reversing/Monitored Entrapment Devices: These provide reversing or stop commands to the gate operator when an obstruction is sensed in the path of the gate.
· Locking Devices: Provide additional locking for the gate system. These devices interface with the gate operator.
Gate Operators have INPUTS: The gate operator is looking at these Inputs. Inputs tell the gate operator what to do and when to do it.
Controls and Accessories have OUTPUTS: These are either a relay or solid-state outputs that send commands to the gate operator.
There are two things that are found in almost any control or accessory:
· Relay Output
· Power for device
Relay Output: Relay contacts provide the commands to the operator or other system.
Power Input Requirement: Most devices operate at one or more of these common voltages:
·
12 VAC, 12 VDC
·
16.5 VAC
·
24 VAC, 24 VDC
·
115 VAC (not that common in today’s accessory and control market)
·
Some will work on multiple voltages, such as: 12-24V
AC or DC.
·
Solar accessories may be rated at 9 to 30 VDC. Solar friendly accessories may also offer low current draw operation or turn
off when unused.
The determining factor would be the power requirement of the accessory. If the operator does not have the appropriate power available for the accessory, a separate power supply should be supplied for the device. The device can then work with any type of operator.
If the device is powered by a separate power supply, then it is a matter of connecting the relay output to the operator. Relays can connect to any operator.
Most gate operators provide low voltage on their control board to power some accessories. This may be 12 or 24V. However, there is a limited amount of power available.
Providing a separate power supply for accessories ensures that too much current is not drawn from the gate operator.
When automating a vehicular gate, or controlling a pedestrian entrance, several factors need to be considered:
· How will tenants/residents or the daily system users gain access?
· How will employees gain access?
· Is visitor access required, and if so, how will they gain access?
· How will vendors or service personnel gain access?
· What type of emergency access is required by the local fire district?
When considering the type of access control devices to incorporate into a system, it is important to identify the level of security and control a property wants to achieve. Some factors to consider:
·
What level
of security is trying to be achieved?
·
Do access devices work 24hr a day, 7 days a week at all access
points, or are there
restrictions?
·
Does a person need to be at the door or gate they are opening,
or can they open the gate
remotely?
·
Do the customer want the ability
for a resident to share codes with other people and allow them to have access into the
property?
·
Does the access device
need to match or interface with other systems,
for example cards that work with resident door locks,
or access devices that match other properties owned by the same company?
·
What level of convenience should the access
device provide?
·
Are there different types of devices
to provide options
for residents or system users?
There are two basic forms of access control
systems: Stand alone or access controller
based. Care must be given when
specifying access control devices.
Many devices
look alike, even if they are stand alone or access controller connected. Always refer to the manufacturer’s specifications for the correct device
designation for the project.
This type of access control device is self-contained with the capability to SENSE-DECIDE-ACT. It does not require a connection to another control device. All it needs is power and output to input wiring for the operator system to function. These are typically used in smaller gate systems, where the population of residents or primary system users is stable and simple access is required.
This type of access control device can SENSE but is dependent upon a controller unit to DECIDE- ACT. It requires a connection to the control device via hardwired or wireless connection.
These systems often provide the ability to program from a PC or cloud database, making it easier to keep the programming up to date. They also provide more advanced functions, such as the ability to restrict access based upon time, day, and access point. These systems can also track and store activity.
The ability to selectively control the time of day, or the days of the week that a card is valid is also a key feature of more sophisticated access systems. The card access software can store the day, date, time, and identity of each card used for later retrieval.
Reports
are available that would provide
a hard copy of each activity with the gate:
date, time, and card number. Although typically used
with card readers, these reports can be available with keypads and radio
controls.
Card access systems have become a primary product line in many industries. The more sophisticated the application, the more likely a security contractor will sell the access control system of which the gate access is a part of the total security package.
The access industry
of today uses sophisticated technology that permits programming,
troubleshooting and other functions from a remote
location using a personal computer.
Proximity cards can hold more data than a magnetic stripe
card, for example,
an electronic funds balance,
and can be used for contactless payment systems.
There are several different formats and technologies used for connecting the access devices to the main access controller. This may affect the choice of device depending upon the connection requirements, distance the access point is away from the access controller, and desired programming functions.
The following are a few examples, but always refer to the manufacturer’s instructions for details
on specific equipment.
·
RS-232, serial
connection. This is typically limited
to 50-100 ft of wiring
to controller.
·
RS-422,
alternate serial format. May run up to 1000ft cable but may require special adaptors.
·
RS-485,
these use proprietary formatting, meaning the access device and controller
must be the same brand and match the formatting. Wiring
distances to the access points
are up to 4,000 ft.
·
26-bit Wiegand,
this is the standard bit format for most card readers and access devices.
It is an SIA Standard (Security Industry Association). This allows for mixing and matching access
devices and access controllers. Many access control system manufacturers have
adopted Wiegand technology. This typically provides wiring runs up to 500ft,
with device codes using a 3-digit Facility code (0-255) and a 5-digit access
code (00000-65535)
·
Proprietary Wiegand
formats are additional Wiegand bit formats
that provide higher
levels of security. These are typically proprietary, meaning the access
devices and access controllers must match. Each manufacturer may develop their
own formats with varying complexity of field numbers and lengths and parity
checking.
Access devices
require connections to the gate system (if standalone) and/or the access controller
unit (if not standalone). The type of unit specified will determine the number of conductors required for the connection.
Always refer to the manufacturer’s guidelines for the proper gauge and type of wiring to be used to make the connections. Not all wiring is the same; refer to the Electrical Chapter for clarification of cable types to be used.
Technology allows for the connection of access devices to the gate system or access controller unit by means of wireless equipment. This method of connection can be of significant cost savings but is limited to distance and line of site based on the wireless signal.
Always refer to the manufacturer’s guidelines for the limitations of this type of connection equipment. Wireless Weigand devices do require a power source, so conduit and wiring must be considered.
However, instead of sending the Wiegand code through wires, these devices connect wirelessly with the access controller. This can eliminate long wire runs from the Weigand device to the access controller and can simplify installation, saving time and money.
Wireless devices are
becoming increasingly popular because of the time and labor
savings they can provide an installing dealer.
A mesh wireless network is a type of networking where each access point (node) must not only capture and disseminate its own data, but it must also serve as a relay (or repeater) for other access points. In this type of network, the message (RF signal) from the access point is transmitted along a path by hopping from node to node until the access controller is reached.
To ensure all its paths’ availability, the network must allow for continuous connections and must be able to route the RF signal around broken or blocked paths. The self-forming and self-healing mesh network capability enables access devices to continue to operate when one device breaks down or a connection goes bad.
As a result, the network is typically quite reliable as there is often more than one path between an access point and the access controller. It also extends the range of the wireless network and improves reliability.
A mesh network is not only inherently reliable, but also highly adaptable. If access control points are too far apart for a solid RF communications link, one or more repeater nodes can be added to fill the gaps in the network.
Shortening the
distance between nodes can dramatically increase the RF link quality making the
links more reliable.
TCP/IP communication
method used by internet connected devices which can allow an access control device to communicate to an
internet-based cloud data storage and distribution hub. The connection method
for TCP/IP is usually ethernet or Wi-Fi, either of which can provide a higher
speed connection compared to older technologies. Ethernet cables can usually
run up to 100 meters with a single cable.
These are the most basic controls for gate systems. For safety reasons, they should be installed so the user has a visual sight of the gate area being controlled.
Consult the manufacturer’s installation instructions for information on each product.
These are typically used in a manually controlled gate application where a guard or agent is opening and closing the gate system from a specific location.
These may be interior or exterior controls. Options included momentary activation of the gate, or a hold and lock open function.
Radio controls are commonly used in both residential and commercial gate operator installations. A radio control consists of one or more transmitters and a companion receiver.
The transmitters send a coded radio signal to the receiver unit. The receiver unit is located inside the gate operator’s enclosure and usually has a remote antenna that is placed outside of the gate operator to increase reception range. Various frequencies are available for the transmitters and the receiver, and the radio frequency (and coding) must be the same.
The range of a gate operator transmitter to activate a receiver varies and is very site dependent. Ranges typically range from 50 feet to 300 feet, but a transmitter should only be activated when the user is within a clear line of sight of the gate panel.
Gate operator radio receivers typically come with a coaxial connector Type F or BNC. For enhanced radio range, the antenna should be remotely mounted using coaxial antenna extensions.
For best range and radio operation, it is recommended to mount the external antenna above the height of the gate. Radio reception can be interfered with by high-voltage power lines, microwave towers, airports radio frequencies, military bases, and other nearby radio signals.
In these situations, using a radio control system on a different frequency may help. The digital coding of radio signals helps ensure system integrity. There are two general types of digital coding: fixed code and rolling code.
Fixed Code: Typically, DIP switches, which consist of a set of rocker switches for setting the code. The DIP switch settings in both the transmitter and the receiver must be matched to the same code to enable correct communication. A ten-switch transmitter that has two rocker switch positions will allow for 1,024 different code settings. Some transmitters have nine DIP Switches with three rocker switch positions that allow for many more different code settings.
Some transmitters have no DIP switches, but have a code preset at the factory that must be taught to the receiver. This factory set code may contain a million or more different code settings. With this type of system, an installer or user cannot change the code setting of the transmitter or receiver.
Rolling Code: This is a newer method of setting a code, where the code is generated by an encryption algorithm within the transmitter. This style of matching the transmitter to the receiver
is done on site per a set of instructions to match each brand. This style is more secure than the DIP switch type because:
· It typically has more code combinations and
· It offers higher levels of security, preventing prevents replay attacks (code grabbers) from operating the system.
Multiple Frequency Systems: Up until recently, all transmitters were factory set to only one frequency and one code type. Newer transmitters can now output multiple frequencies, and some can output multiple code patterns.
Some of the newest radio controls now have transmitters outputting two or three different frequencies whenever the button is pressed and a companion receiver that can scan and receive multiple frequencies. This allows better reliability and performance. If one frequency has interference, the system automatically scans for a frequency that will allow the signal to go through.
Multiple Code Transmitters: Typical transmitters are factory-set to one code system (e.g., DIP switch or rolling code) and can only be used with a matching companion receiver. Multiple code or universal transmitters are designed to transmit a variety of codes.
A single transmitter can be setup to output a DIP switch code or a rolling code, making one model of a multiple code universal transmitter the replacement transmitter for different radio control systems.
Credentialed Transmitters: Transmitters may or may not include embedded Wiegand
data. This is an important consideration if the site plan expects
to use the output from a radio to tie in
with a larger access control system.
Beginning in the mid-1990’s, the US automobile manufacturers began adding a built-in garage door opener (and thus a gate operator) transmitter to their vehicles. A well-known and widely incorporated system is HomeLink®.
The HomeLink® transmitter can clone itself into a garage door or gate operator transmitter, including DIP switch, factory- set and rolling code transmitters. Instructions are provided with the vehicle for the car owner to train their transmitter.
Some radio transmitters do not allow cloning into an automobile transmitter.
The advantage of using radio controls is that no stationary access controls are needed beyond the fence line. This can reduce vandalism and provide additional security. A lack of adequate space between the roadway and the fence line is another situation where radio controls are the preferred solution.
When using radio controls in the gate system design, determine what type of control is preferred.
· Is the control built into the gate operator or access system?
· Is there a need to match other radio control transmitters, such as garage door openers in the community?
· Does the customer want to allow or prevent transmitters from being learned into automobile transmitters?
Drawing 50-6007
Card readers are a
commonly used method of controlling access through a secured gate or entry
point. The user must present a digitally coded card to the card reader. The
reader verifies the code and grants access
for valid codes.
There are a wide variety of card reader types available:
·
Insert card readers require
the card to be inserted into a slot to be read. A possible drawback to this
type of reader in a hostile environment is how easy it is for a vandal to block
the slot with almost anything and stop access to the facility.
·
Swipe card readers
require the card to be passed through
a slot to be read by the electronics. This type avoids the
issue of tampering as described above.
·
Touch plate card readers have neither
a cavity nor a slot; the card is placed
flush against the surface to be read.
·
Proximity card readers
do not require
an insert or swipe, merely
the presence of the card within a specific range of the
reader. This read range can vary from just a few inches up to several
feet. These have become the primary type of reader
on the market today. This functions on 125kHz.
·
Bluetooth Readers are
becoming more available. These are a
type of reader with a Bluetooth antenna, that connects with an app on the smart phone. The app functions like a card providing an access code and
interfacing by Wiegand connection back to the controller. Some of
these readers have a dual function of Bluetooth reader and standard
Prox Card reader.
·
Mifare Readers are Prox
readers that utilize a different technology, working on
· 13.5MHz. These cards are also called “smart cards” and can have memory and information stored on the card. These are becoming more popular as “door keys” to apartments and condos, offering much higher levels of security coding. These also may have a standard 26-bit code included in the programming, allowing the card to also be used for regular access around a property. Mifare cards come in two formats:
·
Universal ID, the card has
a 26-bit Wiegand coded embedded in the Mifare
programming. Cards are universal and
may work with different types of readers or access controllers.
·
Encrypted, these cards have an encrypted access code and must be matched with an
encrypted reader. This offers a high
level of security.
Passive cards/key ring FOB, the more widely
used type, are powered by radio frequency signals from the reader device and so have a limited range and
must be held close to the reader unit. They are often used as keycards for
access-controlled doors and gates, library cards, contactless payment systems,
and public transit fare cards.
Active cards, sometimes called vicinity cards, are powered by an internal lithium battery. They can have a greater range, up to 30 feet, and are often used for applications where the card is read inside a vehicle, such as security gates which open when a vehicle with the access card inside approaches, or automated toll collection.
However, the battery
eventually runs down, and the card must be replaced after five to seven years.
The integrated circuit contains a receiver which uses the battery’s power to
amplify the signal from the reader unit so it is stronger, so it can detect the
reader at a greater distance away. The battery also powers a transmitter circuit
in the chip which transmits a stronger return signal to cover the greater
distance.
This method of access control utilizes a proximity tag or barcode tag for each vehicle. The tag has an identification number that is received by the antenna/scanner. This number is processed in the same manner as a standard card reader.
When utilizing the
A.V.I., the driver is not required to take any action to be identified, and the
activity of the vehicle may be recorded
automatically. Tags must be mounted
on the vehicle where it can
be read by the system.
Another variation of this system is a reader capable of working with highway toll tags. This provides address to the gate system using an access code embedded into the toll tag.
Newer technologies are coming into the market that use smart phone apps to provide control of a gate system. In residential properties, this may be a simple app showing the status of the gate and allowing the user to OPEN or CLOSE the gate.
In commercial or multi-family applications, this may be an app allowing control of one or more relays in the access control system.
One consideration for app-based control is the level of security that this provides. With an app- based access device, a resident or system user can open the gate from anywhere.
They do not have to be at the door or gate they are opening. This may or may not be desired by the property owner.
For higher levels of security and control, often the customer will want a person to be at the door or gate they are granting access to, not sitting on a beach in Hawaii.
However, in other, lower security applications, the benefits of an app-based control may be preferred over the loss of security and control.
Digital keypads allow for the secured operation of gate operator without the use of mechanical keys, cards/fobs, or transmitters. The entry of a proper code number will activate the gate operator. These may be stand-alone systems, or a Wiegand/RS-485 keypad to tie into an access controller.
Some models provide a single code, and more sophisticated models allow each system user to have an individual code. Since someone may enter multiple codes to find a valid access code, most digital keypad entry systems now allow for “Three strikes and they are out” feature.
This means that following three invalid codes, the system will no longer respond to entries being made, even if one is a valid number. The time that the unit remains non-responsive varies and is sometimes adjustable.
Drawing 177-6006
Keypads provide simple access for gates. These are often used in residential applications where the homeowner has full control of who gets the codes. However, in multi-family or commercial applications, some consideration must be given to the ease of personnel giving out their code number to unauthorized persons.
A resident or system user can easily
share their code with other people, giving
them full access through the system. For this
reason, the digital keypad units are not practical for high security applications.
An automated gate system will often include a method for granting access to visitors. The most common method for controlling this access is with a telephone entry system. In more complex and sophisticated systems, the telephone entry unit may also provide control of access devices such as keypads, card readers or RF controls.
This now becomes a telephone entry and access control system. The telephone entry system provides communication from a secured entry point to a resident, tenant or into a building, by communicating through the telephone lines.
Once communication is established, the person at the gate can speak with the person inside the property. If the resident/tenant wishes to grant access, they can dial a number on their telephone, which in turn activates a relay inside the telephone entry system (TES).
New technologies are coming into the market that provide more advanced features and options. These may include video calling and other applications intended to tie into resident smart phones.
In a telephone entry system, the type of telephone line may be critical in the operation and performance of the system. Traditional “land lines” are a thing of the past.
There are now many options for VoIP, fiber, cable, or cellular phone service. Check with the equipment manufacturer of the entry system to ensure the proper type of phone line or internet connection is available for the entry system. In many cases, providing the telephone service for the entry may be an option and can significantly improve the performance of the system.
Traditional hard-wired intercom systems require low voltage wiring from the entrance to the residence/office. It enables the visitor to make their presence known by pressing a button to call into the residence/office.
The owner would then answer at the internal
call station. The capability of an intercom
to activate the gate depends
on the brand and model.
If it is not an internal part of the intercom, then extra wiring would be needed to control the gate. The cost of the components must be weighed against the cost of installing the wires. The farther the outdoor station is from the indoor station, the less practical the hard-wired intercom may be.
There are also Ethernet based intercoms available that use the building Ethernet infrastructure to provide point to point communication,
A wireless intercom system is a voice communications system which uses a transmitter and receiver at each end of the communications points. A power source is required at both locations.
The same site
conditions that can cause interference which were addressed with radio controls
apply to wireless intercoms. The elimination of hard wiring between the gate
and the home/office is an obvious enticement. The site conditions need to be
evaluated before taking this option.
Biometrics refers to the quantifiable data (or metrics) related to human characteristics or traits. Biometrics identification (or biometric authentication) is used as a form of identification and access control. It is also used to identify individuals in groups that are under surveillance.
Biometric identifiers are the distinctive, measurable characteristics used to label and describe individuals. Biometric identifiers are often categorized as physiological versus behavioral characteristics.
Physiological characteristics are related to the shape of the body. Examples include, but are not limited to, fingerprint, face recognition, DNA, palm print, hand geometry, iris recognition, retina and odor/scent.
Used for years in higher security and time keeping applications, biometrics is relatively new to the automatic gate industry. There are several manufacturers that are offering or developing equipment for the gate industry.
Always refer to the manufacturer’s specifications and guideline for the proper installation and
application of these devices.
There are several manufactures currently producing products that require sequential access inputs from two devices to operate the gate system. Card readers used in combination with a keypad have been used in higher security projects for years.
If asked to design a
system using a combination of access devices used in
conjunction to active the gate system, always refer to the manufacturer’s
guidelines and specifications to insure compatibility of the devices for operation
and programming
Remember, the UL 325 standard restricts any controls being within reach of the gate panel or the gate operator. This applies to all access controls devices. See drawing 12-2006.
The minimum
distance between all access controls
and the moving
gate panel and operator is six
feet. Intent is to prevent
the user from reaching over, under, around
or through the gate to operate
the controls.
Drawing 12-2006
Failure to follow this requirement is a common
cause of personal
injuries involving gate operators.
An exception to this is emergency access
controls may be placed at any location
in the line-of-site of the gate.
UL provides a 6ft minimum spacing. However, for drive up gate systems this is not really a practical measurement. It may not allow a vehicle to get their driver’s window even with the device before the front of the vehicle is hitting the gate.
Controls that will be used to access the site from a vehicle are recommended to be placed a minimum of 12 feet from the gate/fence panel as a norm. Due to the site conditions, types of vehicles, as well as the system users, this measurement may need to increase to 15 feet.
Longer vehicles, along with turns in the gate approach and drivers with diminished
depth perception should be considered. Care must be exercised in access control
device placement with swing gate systems if the control device is to be located
on the swing side of the gate.
Drawing 177-6006
Drawing 88-3006
Drawing 1783007
Most pedestals provided by manufacturers have an average height of 42 inches. With the number of mini vans, pickup trucks, and SUV’s on the roads today, this may not provide the best access.
When considering the placement of the device
from the gate,
the designer should
determine how high above
grade the device
should be placed.
Taller pedestals and dual (high/low) pedestals are
available and should be specified when needed. It is not only important to
limit access, but also just as important to not limit or restrict the flow of
traffic.
Any device placed in front of a gate which is to be used for access control by a driver should be protected from vehicular damage by the installation of bollards. These vary widely in size and strength, and should be located near, and slightly forward of, the access control device.
The installer can be creative in how to make the bollards match the site conditions, but bollards are essential in preventing damage to the more expensive access control devices.
See drawings next page showing
pedestals and bollard
placement.
Drawing 52-3001
Drawing 52-3002
ADA mounting requirements for access controls for pedestrian doors are applicable to pedestrian gates. The local authority having jurisdiction should be consulted for requirements.
A pre-defined set of rules used to grant or prevent access when assigned
to personnel. An access
level is a combination of doors/gates and time zones (ex. Card authorized for Door 1 Mon- Fri 8AM
– 6PM).
A feature that restricts the user passing through a defined Entry point into a facility. There are typically two versions of this feature.
· Timed anti-pass back does not allow reentry for X amount of time (programmable)
· True anti-pass back never allows reentry until the user exits the property. There is a variation of this where the system resets at a specified time and allows entry the following day.
The ability to program the access system relays to operate at specific times and days throughout the year to lock open/close the gate or doors.
Code used to initiate call to tenant.
The keypad code used to access the gate or door.
This can be a combination of numbers and letters ranging in the number of characters. This is dependent on the manufacturer of the product.
3-digit code specific to an overall installation which increases the available number of cards/transmitters that can be issued before any repetition of card numbers occurs.
Site specific programming to allow access by users to restricted days/hours for entry (ex. Monday
- Friday 8
AM - 5 PM)
· Understand the role, various technologies, and key parts of vehicle detection systems in automated gate operations.
· Recognize different vehicle detection technologies like loop detectors, ultrasonic sensors, and radar, understand their uses and benefits, and learn how to install and calibrate them.
· Learn how to connect vehicle detection systems with various gate operators, understand the wiring and communication, and fix common issues to keep them working properly.
· Set up security measures to protect vehicle detection systems from tampering and unauthorized access, understand the need for regular maintenance, and use best practices for troubleshooting and keeping them reliable.
· .
Vehicular gate systems incorporate moving gate panels opening or closing across a roadway opening. This is to control the movement of vehicles through the entry point. There are different technologies used for vehicle detection, and various ways to use these technologies. Vehicle detection is used for many reasons in an automated gate system:
· Identifies a vehicle when it is present in a defined area and provides a signal to the gate operator.
· Adds convenience to the operation of the gate system.
· Helps minimize the potential for the gate to close when a vehicle is present.
· Improves the timing of the gate closing cycle.
· Improves security, limiting function of access devices.
UL 325 addresses entrapment protection devices only as they may be applied to the welfare of personnel, and not vehicles. For this reason, there is no mention of vehicle detectors in UL 325, as they would not serve to protect an individual. This is not to say that vehicle detectors are not an integral part of a gate operator system, they simply do not apply to entrapment protection as defined by UL 325.
There are many different functions used by vehicle detection in a gate system. These include the following applications:
An old industry term for this function is safety loop. The term safety loop should no longer be applied to vehicle detectors, since the term safety implies protection, and a vehicle detector offers no protection to individuals.
This vehicle detector function will hold a gate open (if it is already open) and prevent the gate from closing. If the gate is closing and a vehicle is detected, the gate will stop and reverse back to the fully open position. Some operators have the option of stopping the gate instead of reversing the gate. Once the vehicle has cleared the area, the gate will continue to close. Typically, this loop function will also reset the close timer in a gate operator when a vehicle is detected.
The area covered by the vehicle reversing detection is the area immediately next to the gate, both on the inside and outside of the gate. A vehicle detector serving for reversing detection will have no effect on a gate that is fully closed.
Automatic gate systems should only use the manufacturer’s built-in/optional Timer-to-Close feature for auto-closing the gate when vehicle detection is provided.
This vehicle detector function will provide an open command to the gate operator. A vehicle detector serving for automatic exit also serves for vehicle reversing detection. The automatic exit will prevent the gate from closing (by shunting the timer to close).
For all brands of gate operators, if the gate is closing and a vehicle is detected, the gate will stop and reverse back to the fully open position. Placement of the automatic exit detection can vary significantly based upon the desired operation of the gate, and the surrounding area.
Some properties may use this loop in place of the inside vehicle reversing detection, while other properties may want the automatic exit action to start farther up the roadway as a vehicle makes its approach. Be cautious of the placement of this when there is cross traffic inside the gate area.
An old term for this application is Free Exit, which can be a confusing term to an end user.
Vehicle reversing detection for swing gates are typically placed inside and outside the path of the gate. This may create a gap in vehicle detection between these 2 areas.
This could allow a vehicle to stop in between the detection zones. If a vehicle stops in this area the gate could time out and close with a vehicle in the gate path.
A “shadow” vehicle detection system provides coverage for this area. This is designed detect a vehicle when the gate is at the fully open position, which prevents the gate from closing.
Once the gate begins the closing cycle, a shadow detection system must shut down and ignore the gate panel as it passes through this detection zone.
When shadow/center detection has been added, there should be minimal or no zone in which the presence of the vehicle is not detected.
Once the vehicle is cleared of this shadow zone, and the timer-to-close starts the gate to close, a vehicle cannot enter this zone without first passing over one of the two standard detection areas.
The location of this detection system is critical. The shadow/center detection system must be located so that the gate panel does not activate the vehicle detector when the gate panel is fully open or fully closed.
When an in-ground loop system is used, the loop needs to be at least four feet off the gate panel when closed and the end toward the gate when fully open must also be at least four feet from the gate panel.
Although pedestrians should not use a vehicular gate (per UL 325 Standard), there are site applications where additional measures are taken to ensure this does not happen. The placement of detection adjacent to the access control device creates what is called an arming detection.
The relay output of the access control device is run through the normally open set of contacts of the vehicle detector prior to being run back to the gate operator’s open command terminal point. In so doing, a vehicle must be present for a valid access to be granted, or the signal to open never reaches the gate operator circuit.
This also can be used in combination with radio controls, requiring a vehicle to be at a specified area before the radio control will activate the gate.
Used with barrier arms (typically parking control) to lower the barrier arm once the vehicle has entered and cleared the detector, which is directly under the barrier arm.
This form of vehicle detection system is often the least understood component of the gate operator industry. This fact has nothing to do with the excellent reliability of the products, it is the result of installers not understanding how these systems work to detect vehicles.
These systems can be affected by not following the proper installation procedures, basic loop design criteria, and not educating their customers on the function of vehicle loop detectors. To truly be a professional in the gate operator industry, the system designer must become an expert on the installation and behavior of vehicle detectors.
Detection loops are often referred to as magnetic vehicle loops. This is a correct statement because a loop is creating a magnetic field when voltage is introduced into a coil of wire, but the term “magnetic” is a bit misleading.
Vehicle detection loops detect metal using an inductive field. This detects all types of metal, including aluminum gates. The principle behind how the loop works is inductance.
Vehicle detection loops work when a metal object that disrupts the induction field passes over them. Objects that meet these criteria absorb the magnetic field which in turn causes the detector to perform its task.
Installers often place loops too close or worse, under aluminum gates based on the fact aluminum does not respond to magnetism. Aluminum is a good conductor of electricity and therefore does absorb the loop energy triggering the detector. Later in this chapter, we will discuss the sizing and placement of loops to best meet the needs of the site based on vehicle type and use.
System designers must also consider vehicle speeds and traffic patterns when planning quantity and loop placement/spacing. A vehicle moving at 30 mph will cover 44 feet per second. In some situations, it will be necessary to install multiple loops to perform the same task to accommodate traffic speed and flow.
Before getting into the technical details of the following sections, a simplified version of how vehicle detectors and their associated loops work will make reading about this complex issue easier to understand.
Loops are buried in the roadway to create a pattern that has a field of sensitivity (inductance) and is in tune with the surrounding environment. The entry of a vehicle (metal object) into this field is sensed by the vehicle detector and an output, via a relay contact or solid-state output, is transmitted to the gate operator or access device to provide the desired function.
This is the same technology that has been used at traffic intersections to control traffic lights. In gate systems this provides the ability to detect vehicles and provide the many different types of functions as discussed earlier in this chapter.
The inductive loop detection system is comprised of two elements: the electronic detector module and the inductive loop coil with the loop lead-in cable. The vehicle detector forms a tuned electrical circuit of which the loop wire is the inductive element. If a metallic mass passes through the field, eddy currents will be induced in the conducting object. Since the loop inductance is proportional to the magnetic flux, it results in a decrease in loop inductance. The detector senses the change in inductance and actuates its electronic output (an internal relay changes state).
There are many options for vehicle detector modules. The options will vary based upon the manufacturer of the gate operator. Options may include:
·
Plug-In
Detector. This is more brand specific. Some brands of operators use a common
plug-in detector module. While other operators use a brand specific module. The
advantage of these is that they plug into the operator control panel,
eliminating the power and output wiring to the
operator. The loop will still need to connect to the detector.
· External “box” type detector. This is a separate detector component that hard wires to the loop and back to the gate operator. An advantage of these is that they typically can work with any brand gate operator.
These external detectors shown above need to connect with the loop and with the operator for power and output. There are several options for this wiring.
· Wire Harness, this has a connector that plugs into the detector module and provides pig-tail connections for the loop, power, and relay outputs.
The detector plugs into this socket and there are screw terminal connection for the loop, power, and relay wiring.
· Detector Socket, the detector plugs into this socket and there are screw terminal connection for the loop, power, and relay wiring.
· Some detector modules have a terminal block for wiring on the side of the detector.
It is important that the system designer match and provide all components necessary for the complete loop system. This includes:
· Loop Detector Module for each vehicle detection function. Make sure the detector matches
· the operator when selecting “plug-in” models.
· Matching wire harness or socket for external detectors.
· One or more loops for each function, as required for the desired system performance.
The detector module provides an output to the gate operator. This is either a relay output or may be a solid-state output for plug-in detector modules. There are two basic types of output functions:
· Presence output, a maintained output for the entire time the vehicle is being detected.
· NOTE, most detectors are designed to self-adjust as the environment changes. This means that when a vehicle stays within the field of detection, the detector will eventually see this as a permanent condition and retune, dropping the detection of the vehicle. This is typically after 20-40 minutes but can vary based on several factors. Some specialty detectors offer an “infinite hold” option. However, be aware that on these operators, detectors that go out of tune due to intermittent problems will hold the gate open indefinitely.
· Pulse output, a momentary output when the vehicle is detected. This sometimes has the options of:
· Pulse on entry, a momentary output when the vehicle is initially detected.
· Pulse on exit, a momentary output when the vehicle leaves the detection zone.
This term relates to the planned response upon failure of the detector. Since the gate operator industry uses vehicle detectors for the detection of vehicles in the path of a gate, should a fail- safe detector fail it will error on the side of safety.
Fail-safe means that should the detector or the loop fail, the gate will be held open. It is “safer” to not run the gate when the vehicle detection systems are not functioning.
The typical method for providing fail-safe operation is in how the output relay functions. The relay that provides the command to the gate operator’s circuit board is electrically held open (energized) all the time, and then only drops out when a vehicle is detected.
If power is lost, or the wiring to the loop is lost, or is unintentionally grounded, the relay will drop out and thus prevent the gate from closing. In this case, a failed detector will cause the gate to remain open until the problem is corrected.
This term relates to the planned response upon failure of the detector, but with reverse logic. If the vehicle detector is fail-secure, then there is no input to the gate operator circuit board should the power be lost, or the wiring to the loop is lost, or unintentionally grounded. Fail-secure will allow the gate to continue to run when the vehicle detection system is not functioning.
A property owner may ask for a detector designed for special applications, but more times than not it will be an error on the part of those requesting this feature. For example, even a prison application does not warrant the use of a fail-secure detector for a gate system.
An exception to the above comments is valid when referring to an automatic exit loop in a secure application. This prevents an unintended opening of the gate when a power interruption occurs and when power is restored the vehicle detector, the detector retunes and sends a pulse to the gate operator.
This is practically a mandate now at airport gates. Fail-Secure detectors are typically a special- order item.
Detect-on-Stop technology activates only when a vehicle comes to a complete stop over the sensing element (i.e., inductive loop or magneto resistive sensor). This technology helps minimize false activation due to cross traffic in tight spaces.
A variation of this is a detection delay. A vehicle must be present over the loop for a preset time before the detector sends the output to the gate system.
The loop and lead-in cable are the inductive elements of the detection system and possess a combination of resistance and capacitance (both interwire and wire-to-earth capacitance). The loop wire is wound to form a coil where the magnetic field becomes more concentrated creating the zone of detection.
Each run around the rectangle of the loop is referred to as a “turn of wire”. There are typically 2- 4 turns of wire around the loop, based upon the size of the loop. All conductors or wires carrying an electrical current produce magnetic flux caused by the current flowing through the wire.
The effect of this flux is the electrical property called inductance which is measured in micro- Henries (uH). The loop is tuned to match its environment. Stationary or static metal objects, such as water pipes, metal grates, and rebar in the concrete will not affect the loop field.
However, fluctuating electrical fields, such as heating coils, overhead power lines, electrical transformers along the drive etc., may cause loop lockups and false detection.
The height of the field of sensitivity, and therefore the height of vehicle detection, is determined by the size of the loop. There is a rule of thumb for minimum loop size:
· The usable detecting height of the loop is 2/3 of the shortest side of the loop. Therefore, a 6’ x 12’ loop would have a usable detecting height of 4 feet and a 4’ x 12’ loop would only have a usable detection height of 32 inches!
Consider the application of the gate system, and the types of vehicles that pass through the gate system. To reliably detect all types of vehicles, from motorcycles to high bed trucks, a 6-foot short leg provides the best option for detection.
Some applications may require smaller short leg dimensions on the loops due to physical layout restrictions. However, keep in mind that this will reduce the height of detection.
The height of detection also affects the detection zone surrounding the loop. A loop with 4ft of detection height also has 3-4ft of detection zone surrounding the sides of the loop, and even below the loop if used in a multi-level parking structure.
Loops are generally made wide enough to span the lane where detection is required. Again, this may vary depending upon the type of vehicles that pass through the gate system, the short leg of the loop, and the desired levels of detection required.
The width of the loop is typically the roadway width, less 1-3 feet on both sides. For example, a single roadway with a width of 22 feet would have loops measuring 6 ft. x 16-20 ft.
Drawing 131-4001
Be sure there is adequate separation – three feet minimum – from loops in adjacent lanes to minimize the potential for vehicles in the adjacent lane to be detected. Remember, the short side of the loop controls the size of the detection field.
Loops with higher (and wider) detection zones should be spaced farther apart in adjacent lanes. A good rule of thumb is to use the short leaf dimension of each loop, as the minimum spacing between loops. Therefore, two 6’x10’ loops should be placed 6’ apart. There are exceptions to this when the loops are not in adjacent lanes or are being used for combined coverage.
There are no real hard guidelines when it comes to ‘how big can a loop be’. A common rule of thumb is that the loop area should not exceed 120 sq. ft. (6’x20’ for example). However, this may depend on the application.
Generally, loops up to 120 square foot of loop area will be sensitive enough to pick up motorcycle traffic. For applications requiring larger loops, one option is to use a series of smaller loops to cover the desired area.
If installing loops over 120-square-foot in loop area and smaller vehicles like motorcycles need to be detected, then a vehicle detector with higher levels of sensitivity will offer the best chances of success.
In addition, the quality of the loop has a significant effect on the reliability of detection. Some detector manufacturers offer detectors with 20 levels of sensitivity that can be used on loops up to 6’x44’ in size.
One point to consider in this scenario is that detectors with higher levels of sensitivity may experience more false calls or lock ups based upon the stability of the loop. Always check with the detector and loop manufacturer when working with larger loops.
One of the most variable issues in the gate operator industry is how far a loop should be placed from the gate (C in the drawing above). Leaving too much space between the two vehicle detection loops can cause a vehicle stopping between them to go undetected.
On the other hand, the loop should not be so close to the gate that the movement of the gate results in a response by the vehicle detector. Remember, the loop field of sensitivity extends above the loop, around the loop and even below the loop coil. If a loop has a 48” height of detection, this will also provide 48” surrounding the loop at ground level.
To determine the distance the loop should be installed away from the gate, there are two factors that need to be considered:
Height of detection, and length of the short leg.
In general, use the short leg dimension (side B) as a guideline for spacing the loop away from the gate or the arc of a swing gate. This will minimize the potential to detect the gate, while providing good coverage around the gate.
Loop placement is commonly four to six feet from the gate panel, with a loop installed on each side of the gate panel. If done properly, for these type gates the two loops will then be eight to 12 feet apart. In all cases, there is to be a vehicle detection loop of both sides of the gate.
Drawing 137-4008
Drawing 136-4010
Drawing 139-4011
For swing gates that swing inward, the outside loop should be placed four to six feet from the gate. The inside reversing loop should be placed 4 feet beyond the arc of the gate on the side the gate swings toward.
Depending on the size of the gate, the above instructions may result in a long span between these two loops. For example, with a 16-foot single gate, the span between the two loops would be the total of 5 + 16 + 4 = 25 feet.
In this case, the installation of a shadow/center loop is needed. It is the responsibility of the gate system designer to determine if a shadow/center loop is necessary and that need cannot be avoided simply because the customer did not ask for one.
Drawing 179-4012
Drawing 138-4013
There are three basic types of wired loop installations.
The installation of these types of loops requires cutting the roadway surface and installing the loop wires on site from a (bulk) roll of appropriate wire. The use the correct type of wire is critical in the reliability and life of the loop. XLPE (Cross-linked Polyethylene) wire is preferred for hand laid loops.
These loops are normally installed into slots cut in the roadway surface. Cuts are typically made with a roadway cutting machine, with the depth of the cut not less than 1.5 inches.
The shape of the loop is typically a rectangle but where the corners meet there are two cuts, each 45 degrees, to avoid having to bend the loop wires 90 degrees. There is also a cut from the loop to the edge of the roadway to allow the loop leads to run back to the vehicle detector (typically located inside the gate operator housing).
A preformed saw cut loop is a loop that has the proper number of loop windings for the size of the loop and length of lead-in enclosed within a protective jacketing or sleeve. This is designed to slip into a roadway saw cut.
The saw cut grove MUST BE cut to the proper size per the manufacturer’s instructions for the loop to fit properly. Some types of preformed saw-cut loops will have a wire gauge of 16 AWG or larger and incorporate an outer wire jacket to insure protection of the wire insulation during installation and road surface movement from cracks and heat.
Options may be available for saw-cut loops that are pre-phased at the factory, taking the guess work out of properly phasing two loops to a single detector.
Preformed direct burial loops are designed to be used at sites where the roadway surface has not yet been poured. The property owner may request that the loops be installed prior to the completion of the roadway so that no saw cuts are visible.
A second application for preformed loops is where there is no hard roadway surface, such as a dirt or gravel driveway. The loop may be placed in a trench and re-covered with the dirt or gravel from the trench.
This type of installation has two major advantages over a surface saw cut. First, the loop location cannot be seen, so in the case of an automatic exit loop, there is less chance of the security being breached by someone throwing a metal object over the loop to open a gate from the outside. Second, when installed properly the loop life is greatly improved.
In today’s world there is an increasing demand for bicycles to use the traffic lanes. This is often
seen in urban areas, or in areas near college student housing.
Bicycles can be detected by loop systems, but they create a smaller change in the loop field of detection. Providing a separate loop detection system, using specially designed loops, can provide reliable bicycle detection.
There are 3 types of loop designs than can enhance bicycle detection:
· Diagonal Loop. This is a loop that is laid across the flow of traffic at a diagonal. Bicycles passing over the loop affect more of the eddy currents of sensitivity, creating more change in the detector.
· Di-pole Loop. This is a loop with the loop wires run in a figure-eight configuration, creating two loops phased to enhance detection in the middle of the loop area. This type of design is often seen in left-hand turn lanes at a traffic intersection.
· Diagonal Di-Pole Loop. This provides the highest level of bicycle detection.
More on next page.
Diagonal Di-pole Loop
Drawing 141-4016
In-ground loop systems have been the industry standard for vehicle detection for decades. However, there are many emerging technologies adding to the vehicle detection options available.
These new technologies may offer a less intrusive installation and provide good options, especially for retrofit installations into existing properties. Depending upon the type of detection technology, these can provide the same functions of presence, automatic exit, shadow, arming and down vehicle detection. (Note: Some technologies may not be capable of presence detection).
These devices detect using a small sensor probe in the roadway, replacing the traditional loop. They measure small changes in the earth’s magnetic field and can provide pulse or presence operation. Some models may have the option of providing “infinite presence”, meaning they will hold the detector for as long as a vehicle is within the detection zone.
This technology uses the earth’s magnetic field for the detection of moving steel instead of setting up its own field, as with the standard loop system. Using the earth’s magnetic field for detection has several technical drawbacks that must be taken into consideration:
· These probes detect moving metal. If a vehicle stops, the probe will lose detection of the vehicle. Therefore, these cannot be used for functions which must detect a vehicle that is stopped. Probes are typically only used for automatic exit functions.
· There is no set sensing zone, so the sensor must be back from traffic: at least 35 feet back from residential traffic, 50 feet back from highway traffic, and 80-100 feet back from high-speed trains. Having this setback will eliminate most commercial and industrial applications because of the traffic inside the gate area. This limits these applications to residential driveway situations.
· Since the sensing is mass and speed sensitive, the sensing zone is held within a 12-foot- wide driveway area for automobiles at driveway speeds, and beyond the 12-foot driveway area, the sensing drops off very rapidly and is unreliable. This creates a drawback if the driveway is wider than twelve feet. Guests leaving will need to swerve toward the side of the driveway where the sensing probe is located to assure the gate automatically opens.
There are also some advantages to using the earth’s magnetic field for the detection of moving steel as an automatic exit function. These include:
· It is a proximity device where the vehicle does not have to drive over the sensor as with the standard loop system, allowing a much easier and lower cost installation, by burying the sensor in the dirt beside the driveway.
· There is not a distance limitation between the sensor and the electronic control as with the loop system. With the sensor buried 80-100 feet or more back from the gate, this allows the open command for the gate to be placed far up the roadway, starting the gate cycle as the vehicle is approaching and enabling the gate to reach the open position by the time the vehicle arrives at the gate.
· There is no depth requirement as with the standard loop system. The sensor probe can be buried six inches to three feet under the earth and will still work well for vehicle movement. The sensor probe can also be mounted above the ground in a non-steel pipe on a wall, or inside a non-steel building on a wall next to a drive-up window and still work well. A benefit of burying is that the sensor probe is hidden under the grass several feet from the gate operator and provides excellent security from intruders opening the gate.
· The technology allows for extremely low standby current from one milliamp to as low as 40 micro amps which is super solar gate friendly.
Another application for this type probe sensor is to alert the residence that a vehicle is approaching the house. Regardless of whether the gate has a controlled entry or not, the sensor can be used to sound a tone inside the residence when a vehicle starts up the driveway.
· DO NOT bury the sensor probe within 35 feet of residential street traffic.
· DO NOT bury the sensor probe within 50 feet of highway street traffic.
· DO NOT bury the sensor probe within 100 feet of high-speed railroad traffic.
· DO NOT bury the sensor probe within 6 to 10 feet of buried power, telephone, or cable lines.
· DO NOT bury the sensor probe within 6 to 10 feet of a buried invisible dog fence.
· DO NOT bury the sensor probe within 10 feet of a natural gas line.
· DO NOT bury the sensor probe within 20 feet of a power pole with a transformer.
· DO NOT bury the sensor probe within 200 feet of a sub-station type overhead power lines.
· DO NOT mount the sensor probe vertically when used for above-ground applications.
Here
are some examples of probe installation.
There are some new “Virtual Loop” systems that are entering the market. These use different technologies to provide vehicle detection without the use of an in-ground loop or sensor. Some provide detection in a vertical pattern, while others provide detection on all 3 axes.
· Mounts above ground (no trenching or saw cutting)
· Easy installation
· Directional control of detection zone
· Mounts above ground (no trenching or saw cutting)
· Easy installation
· Directional control of detection zone
The overhead cameras seen at a traffic signal are solely for detecting the presence of vehicles to provide the best distribution of green time based on traffic demand. They are cost-effective replacements for in-ground vehicle detection loops that are cut into the pavement.
The cameras are focused on the vehicle as it moves towards the intersection. As a vehicle enters defined areas, or zones, within the camera’s field of view, the camera’s processor detects a change in the zone.
An output is sent to the traffic signal’s controller (the computerized brain housed in a nearby metallic cabinet controlling the intersection’s timing) that says a vehicle is requesting green time for its direction. The same technology is used when these cameras are used for traffic detection at a gate.
·
Understand different types of automated gate systems, their benefits and
limitations, and how to customize them for different needs.
·
Know why backup systems are important for keeping gates working all the
time and learn about different backup options.
·
Recognize how weather and other environmental factors can affect gate
systems, find ways to protect them, and learn best practices for installation
and maintenance.
This chapter covers some additional options or factors that a system designer may need to consider for a gate system. Some of these may be required by state, local or fire codes, while others may be needed to ensure operation due to local conditions.
Historically, when the primary power to the site was lost, the gate would stop working regardless of its position across the roadway. This may be a minor inconvenience for residential and commercial/industrial locations but can be a major issue for gated communities and multifamily applications.
Some state or local codes require that gates default to the OPEN position when power fails. This may also be the desire of the property owner, depending upon the type of property.
There are various ways to address this in a gate system. With the growth of DC operators, it is common for the gate operator to continue working during short power outages.
The question then is how many of the additional controls and accessories may be needed to function when primary power fails?
There are basically a couple conditions that may need to be addressed by the system designer.
These may be required under local codes:
· What happens when primary power goes out?
· Does the gate stop where it is? Even in mid-cycle?
· Does the gate continue to run on back-up power?
· Does the gate default to the OPEN position?
· Does the gate default to the CLOSED position?
· If back-up power is provided, what happens when back-up power fails:
· Does the gate stop where it is?
· Does the gate default to the OPEN position?
· Does the gate default to the CLOSED position?
· If back-up power is provided, how can the gate be opened if back-up power fails?
There may be several options available for back-up power. This can, and will, vary based upon the operator used in the system.
These are all based upon using battery power to run the gate operator and system accessories when primary power is lost. One downside of any system that uses batteries, be it inverter based or native DC, is that the batteries themselves have a finite life and will eventually need to be changed to maintain proper system operation when power is lost.
As discussed in the electrical chapter, battery life is primarily a factor of the number of full (or partial) discharges. Battery life can be further degraded by temperature (heat), improper charging, discharging too much, or discharging too fast.
It is important to realize the differences in battery chemistries and charging technologies and only replace old batteries with the same size and chemistry batteries.
DC operators, by design, are intended to continue to operate when primary power is lost. Primary power (or solar) provides the charging function for the systems batteries. When primary power is lost, the operator will run strictly on battery power. How long the operator can continue to run is based upon many factors, including:
· The size and weight of the gate.
· Number of cycles the gate runs.
· Size and capacity of batteries.
· Current draw of operator and accessories.
One drawback for these types of operators is the number of cycles that the gate runs per hour, or in peak loads. High cycles may drain the batteries before the charging system can replenish them or provide short operation when primary power is lost. To overcome this and other limitations, larger batteries may be used but can add cost and take additional space.
Another factor to consider with DC operators is that the batteries will not only be running the operator, but all the accessories that are powered from the operator as well. This may include radio controls, keypads, and the entrapment devices. All of these, and any other accessories will also require power back-up.
An inverter power system is designed to provide 115 VAC power to the gate system when primary power is lost. This is achieved by using an inverter and a set of batteries.
A power inverter is an electronic power converter that changes DC battery voltage to AC voltage and operates the gate for a limited period based on battery capacity. The input voltage, output voltage, power quality, and frequency are dependent on the design of the inverter.
This battery back-up system is designed to provide a continuous function of the gate operator and all accessories upon the loss of power. The exact number of cycles the system will deliver is dependent upon:
· The total current consumption of the system (unit and accessories)
· The number of cycles the gate is expected to deliver each day, capacity and age of the batteries, temperature, and the ease and duration of operation.
The use of solar friendly accessories can enhance the performance of these systems.
Note: A UPS or uninterruptible power supply intended for computers are usually not capable of handling the high amperage draw and inductive loads of gate operator motors. DO NOT USE THESE DEVICES ON A GATE SYSTEM.
An inverter can produce square wave, modified sine wave, pulsed sine wave, or sine wave depending on circuit design. The two dominant commercialized waveform types of inverters are modified sine wave and pure sine wave. These are graphically shown below.
The waveform in commercially available modified sine wave inverters is a square wave with a pause before the polarity transition. This creates a step up and stepdown type sine wave. Most AC motors will run on MSW inverters with an efficiency reduction of about 20% due to the harmonic content.
This drop in efficiency produces additional heat in the motor which may affect performance such as duty cycle. It is important to realize that modified sine waves have a significantly lower power quality than pure sine waves which may have a negative effect on some circuitry such as current sensors, reversing systems, and motor overload systems used in many gate operators.
Pure sine wave inverters are more complex than a modified-sine-wave type of the same size.
However, these provide better interaction with the current sensor reversing circuits and/or motor overload circuits found in gate operators.
Prior to installing the backup power system, consider where the unit will be installed. The system operates best when it can be installed as physically close as possible to the equipment that it is intended to operate during power outages.
This reduces the potential for voltage drop. The back-up power system also acts as a power distribution panel. Main AC power enters the back-up power system and is distributed through the unit to the gate operator and all accessories. Also consider the required conduit runs when selecting the back-up power supply mounting location.
This type of back-up system was designed to provide a onetime open-only function for the gate operator and should not be referred to as a battery backup system. This system employs a controller, a DC motor, and batteries.
The system monitors the incoming A/C supply voltage, and when that power is lost, the controller logic activates the gate operator to the open position immediately or the gate may remain closed while waiting for a command to open the gate using the DC motor.
Once the gate is open, it remains in that position. This type of system was a popular method for meeting state, local or fire codes requiring the gate to open when the power is lost. However, with the changes in UL 325 requiring monitored entrapment devices, this option may no longer be desirable.
With this type system, all access system components (telephone entry system, card readers, RF controls, loop detectors, entrapment prevention devices, etc.) do not function upon power loss. This system is incapable of maintaining normal gate and access system operation during power outages.
Before supplying this type system to a customer, discuss the balance between convenience and security; there are a lot of applications where power loss should not automatically result in an open (unsecured) gate. Some operators must be ordered with this option installed from the manufacturer and may not be installed in the field without extensive labor cost.
When a gate system is “automated”, a method must be provided for emergency responders to access the gate system. Many municipalities require specific equipment and procedures for emergency responder access.
Simply installing a “fire access box” may not meet the specific requirements of the local codes. A system designer should know and understand the local and state requirements for this critical site access.
Some of the more typical emergency access equipment available to the industry include:
· Fire Box (Knox Box) equipped for padlock access or key override
· Siren Operated Sensor
· Strobe Light Detection (Optical)
· Radio Frequency Recognition Receiver
· Dedicated secured keyway padlocks/switches
· System Battery Open Drives on power loss
Questions to clarify with the local and state code officials might include but is not limited to:
· What is the primary access device required to open the gate for emergency responders?
· Is a backup device required should the primary operator become damaged or inoperable?
· How is the gate to be opened manually in the event of power loss to the site (back- driveable, manual disconnect, etc.)?
· If special keyed padlocks (KNOX or equal) are required, who is authorized to provide them and is company required to have an authorization form signed by the Fire Marshal to order them?
· Must both entry and exit gates (if separate from each other) open when the primary access device is triggered?
· Must all gates on site be equipped with emergency overrides or will a single-entry point suffice?
· Must the gate/s be equipped with convenience open options to automatically open during a power loss regardless of circumstances?
· Do the overrides allow fire, ambulance and law enforcement access or should each entity be contacted separately?
Note: UL 325 states that access control devices must be a minimum of 6ft from the gate or operator. There is an exception for emergency responder access. These may be placed closer to the gate.
Drawing 49-3003
In colder regions, a heater option may be required for the gate operator, and possibly, some of the accessories. Most manufacturers provide this option as either factory installed or as an accessory. Placement of the heater is important. The heat from the heater can damage batteries and melt plastics that are too close. Without a heater, temperature extremes can have an adverse effect on the gear lube or hydraulic fluids of the operators drive system.
Since the Type A entrapment device cannot tell the difference between a physical gate obstruction and partially frozen gear/hydraulic oil, it is important for designers and installers to factor in for a heater. Low temperatures can also adversely affect batteries, in some conditions, reducing their capacity by as much as 50%. Depending upon the type of entrapment devices being used, heaters may need to be added to these devices to ensure proper operation.
As was discussed in the Access Device chapter, protective bollards may be installed to prevent vehicles from hitting the operator, or any other emergency responder devices, etc. There are many ways to be creative to make the bollards match the site conditions, but they are essential in preventing damage to the more expensive equipment.
A vehicle moving at 30 mph will cover 44 feet per second. A gate moving at one foot per second does not have a chance at getting out of the way.
For an automatic gate system to perform its job, a method for
controlling the speed of vehicles approaching the gate system may be needed.
Speed bumps, or roll overs, can be useful for slowing traffic when installed
properly.
·
Understand the need for high security in automated gate installations,
learn about different security levels and their uses, and identify key parts of
high security gate systems.
·
Recognize different types of high security gates like crash-rated gates
and bollards, understand their uses and benefits, and learn how to install and
maintain them.
·
Learn how to connect advanced access control systems with high security
gates, understand the technologies used, and use these solutions to improve
security.
·
Set up security measures to protect high security gates from tampering
and unauthorized access, understand emergency response plans, and apply best
practices for maintenance and troubleshooting to keep the gates reliable.
This chapter will discuss special applications requiring higher levels of security, or increased control of vehicle traffic. These include:
·
Gate Locks
·
Traffic Spikes
·
Camera Systems
·
Sallyport and Entry Control
Points, providing vehicle
trap systems.
·
Vehicle Barriers / Crash Barriers
Gate operators have built-in methods of locking the gate or restricting the ability to manually push the gate open unless the manual release is engaged. In many applications, electric locks are used to provide a higher level of security on the vehicle gate.
The locks ensure that if the chain, rail, or arm is removed from the gate, the gate panel will remain secured. These locks are electrically released and locked by the gate operator during the normal gate cycles.
The lock should also have a manual key release in case of a power failure. Models are available with limit switches that activate the control console indicator lights to show that the gate is both closed and locked.
There is an electrical requirement to interface the gate lock with the gate operator by either a positive limit switch (gate unlocked) or at least a time delay prior to activation of the gate operator. There are environmental factors that must be considered when selecting the type of lock to use.
The use of a lock in an exterior application exposes it to the weather (water/ice/temperature variations etc.) and vandalism. A lock that is good in one situation may not do as well in another, just as a lock that is good in the Sun Belt may not work as well in the Snow Belt.
This a judgement the designer must make to select the right lock to meet the needs of the customer.
Locks are available in a wide range of AC and DC voltages. See the manufacturer’s charts to
confirm what is available.
The conventional method to mount a gate lock is to place the lock receiver on the gate latch post opposite the gate operator. This requires wiring across the roadway to the lock. It also places the lock barb on the leading edge of the gate (see ASTM F2200 Standard about this issue).
A better installation method for slide gates is to place the lock receiver on a separate post near the rear of the gate panel (when in the fully closed position) next to the back-support post. This eliminates all alignment problems with getting the lock barb into the receiver, as well as eliminating the lock barb on the leading edge of the gate panel.
It also eliminates
the need to run electric wires across the roadway. This type of installation
still requires a gate receiver guide on the gate receiver post to prevent
someone from pushing the leading edge of the gate to gain entry.
One factor to consider on slide gates is that the gates often do not stop exactly at the same specific point. Gates are supported by rollers, which may have more, or less, coasting at different times of the year.
Chain drive
operators also must deal with chain “stretching”, which affects the exact stopping
point of slide gates. It may be difficult to get a lock
to properly engage. Talk with the
lock manufacturer about
options to address this.
Drawing 62-3013
Swing Gates: There is no alternative mounting location for swing gates. The lock needs to be on the gate receiver post.
There are additional concerns related to swing gates and locking mechanisms.
·
A vehicle
pushing against the gate can often overcome
the lock and force the gate open.
·
This may damage the gate panel and operator, in addition to damaging the lock.
In this type application, one gate panel must begin to open before the other, and the same when closing. One panel must reach the fully closed position prior to the other.
The panel that is the last to close must have the locking mechanism. Most gate operators now have the delay to close option for bi-parting swing gates to operate properly with locks.
Vertical Pivot Gates:
Consult the manufacturer.
Vertical Lift Gates: Consult the manufacturer.
This is an electromagnetic lock that utilizes power to create a magnetic field to secure a metal plate (also called an armature) on the moving gate panel to the magnetic lock on the fixed gate frame. In a bi-parting gate application, one panel will have the metal plate and the other has the magnetic lock.
Magnetic locks are automatically fail-safe by design. A battery back-up can delay the loss of the locking capability upon power failure, but the battery will not last long holding a magnetic lock.
This type of lock is not built into the frame of the gate and is a surface mount application. Mounting hardware can be used to align the armature and the lock.
A solenoid lock uses an electrical solenoid to change the state of the lock. Although most of these locks are spring loaded to the locking position and then apply power to the solenoid to unlock it (fail-secure), it is possible to have the reverse situation. On this type of lock, the spring mechanism holds it unlocked but the power being applied to the solenoid keeps it locked (fail-safe).
This type of lock is commonly used with pedestrian doors. An electric strike uses a ramped surface/locking latch to catch the door when closed and hold it locked. The locking mechanism is built into the door frame and is spring loaded to lock the door.
The application of power (various voltages available) pivots the locking latch out of the way so the door may be opened. These do come in both fail-secure and fail-safe models.
A fail-safe lock that, upon loss of power, or failure of the lock mechanism itself, will result in the lock being released or unlocked. An application for this type of lock would be a locking gate that is close to a building and would be considered part of the egress system to exit the building. In the event of a power failure (or lock failure), the gate would automatically be unlocked.
A fail-secure lock that, upon loss of power, or failure of the lock mechanism itself,
will result in the
lock remaining secure or locked. An application for this type of lock could be
a prison where security is high and there are no emergency egress factors to
consider that would change the need for maximum security.
Term used with magnetic locks to establish how much force is required to separate the two metal plates while the lock is powered. The higher the rating of the holding force the stronger the hold.
Some locking systems may use a battery pack to back-up the lock power source. In the event of a power failure, the lock remains functional for a specified period, based on battery size and amperage.
The specified period then dictates the size (or better stated, the Amp Hours) of the battery. A trickle charged power supply is used to ensure the batteries are at full charge when loss of power occurs; and this also can recharge the batteries once power has been restored.
The term used in the battery industry to express the length of time specific amperage will be supplied by a battery. For example, a 2-amp hour battery will provide 2 amps of power for a period of 1 hour.
As another example, a 4-amp hour battery could provide 1 amp of power for 4 hours or 4 amps of power for 1 hour. Battery voltage varies during discharge of a battery, so the lock threshold (minimum voltage to still function) must be known when selecting the rating of a battery.
This is a mechanical
lever that is tripped when the gate lock barb is present in the lock mechanism. The limit switch
provides a contact
(N/O, N/C, or both) that changes state to indicate the gate is locked.
NOTE: The higher security type prison locks can provide two lock limit switches; one to indicate the lock barb is present within the lock and another to indicate the locking mechanism is in place to secure the lock barb.
Magnetic locks do not have physical limit switches but can provide (typically as an option) an indication of the lock condition which is the equivalent of a limit switch.
An electrical design
that ensures that is unlocked prior to starting the gate operator to. This is
normally done with a lock limit
switch and a relay (due to different voltages and the need to keep them
separate).
An electrical design that sends a signal to the lock to unlock prior to the signal to the gate operator to run. This design assumes the lock will unlock, but if there is a lock failure the gate operator will still be activated to run.
Varies by type lock and manufacturer, but some electrical locks have a manual keyed release to enable the lock to be unlock even in the event of a power loss or lock failure. If the lock is fail- secure, the lock release could become an important item even though the lock manufacturers may call it an option.
Traffic spikes are devices used at an access point to provide for one-way traffic for vehicles using the gate system. These are often used on exit gates to prevent traffic from entering the access point while allowing free exit from the site.
Spikes can be either active (powered) or passive (unpowered). Some are available with integrated traffic barrier arms.
Traffic spikes are designed with several sharp teeth that are shaped in a way that driving over them in the wrong direction causes the vehicle tires to be destroyed.
The gate system designer should carefully follow all the manufacturer’s recommendations and
safety guidelines when specifying these systems.
Following the manufacturer’s instructions will minimize exposure and can help to reduce risk and liabilities associated with this type of product.
Installers are reminded to always follow the manufacturer’s installation instructions. The guidelines below provide important information regardless of the type or brand of traffic spike systems that are being used.
These are some
important rules to follow when designing a controlled entry/exit system using
traffic spikes.
· Vehicles must pass over the spikes at a 90° angle.
ü Failure to follow this rule will result in tire damage to vehicles crossing over the spike system.
ü Placement of the traffic spike system in the design must be in such a manner that traffic flows over the teeth at a strict 90-degree angle (tire parallel to the teeth). This must be assured for both the front and rear axles of a vehicle.
ü Place spike system where vehicles cannot be “turning” while crossing the spikes.
Most manufacturers recommend a minimum of 15 to 20 feet in either direction of the traffic spike system between any turns or curves in the roadway. Never install traffic spike systems on or near a curve, or in an area where vehicles will not be assured of complete perpendicular passage over the spike system for both the front and rear axles.
This is essential. Vehicular traffic crossing over the spike system at a high rate of speed will cause extreme wear and tear on the spike system, can cause damage to the internal components, and can damage the vehicles tires. It is highly recommended that speed bumps and signage (5 MPH) be used to help control traffic speed.
Warning signs are another component of a traffic spike system that must be used to provide sufficient notice to drivers that a hazard condition exists. These signs also provide a warning to pedestrians and may be required by local ordinances.
Some manufacturers also state that a warning sign is a mandatory component of the traffic spike system. If traffic will be using the entry/exit portal after daylight hours, be sure to use a warning sign that is illuminated during night hours.
Illumination of the teeth is also essential during nighttime. Many illuminated warning signs include a provision for a floodlight that can be focused on the traffic spikes.
By the nature of their design, traffic spikes allow traffic to flow freely in one direction but prohibit traffic from flowing in the opposite direction. This is sometimes referred to as one-way lane enforcement since vehicles can only safely proceed through the traffic lane in one direction. Motorized spikes can be used in two-way traffic lanes.
It is essential that the system designer understand the traffic flow patterns and to fully understand what type of lane enforcement the owner is seeking.
· Take into consideration the location where the spikes will be installed:
· Never install on or near a curve in the roadway.
· Traffic spike systems must be installed on a solid surface (asphalt or concrete) and can never be installed in dirt or gravel roadways.
· Do not install on any inclines, or where the road surface is uneven or in poor condition.
· Avoid areas where there is significant water runoff that may cause damage to the spike system.
· Use caution when specifying these systems near high pedestrian traffic areas.
Some traffic spike systems allow the facility to latch down or rotate the spikes to the down position and lock them in this position. This may be a desirable feature if there is a possibility that traffic lanes designed for one-way flow may need to be used for two-way traffic under certain conditions. Not all spike systems have this feature built-in, so the system designer must be aware of the traffic lane use and the possibility of two-way traffic.
Traffic spike systems have weight restrictions. It is essential that the system designer fully understand what type of vehicles (cars, trucks, buses, fork-lifts, etc.) will be using the traffic lane and what the weight limitations are on the traffic spike system that are being specified.
The capacity of traffic spike systems is typically stated as weight per axle. For example, a heavy- duty system may state that the maximum weight capacity of the system is 32,000 pounds per axle.
Flush or In-ground Mount: Flush mount (or in- ground) systems typically come in three foot or six-foot lengths and are typically 12 inches wide, although this can vary from manufacturer to manufacturer. This type of system mounts into the roadway, requiring excavation, concrete blocking, and crushed rock for proper drainage.
3000 psi concrete is required to secure the spike system in place and to finish the roadway surface. Prior to specifying an in-ground spike system, check with the local municipality and utility companies for regulations, codes, and inspection of the site (if required) as partial demolition to the existing roadway will be required.
Surface Mount: Surface mount systems are easier to install than in-ground systems because there is no requirement for excavation. Surface mount systems typically are available in three-foot sections only as they are much heavier than in-ground systems.
Surface mount systems also have a built-in rise that needs to be considered when specifying surface mount systems. This rise (also known as a built-in speed bump) can be from 1-1/2 inches up to 4 inches, depending on the make and model of the spike system being used.
Small sports cars that are low to the ground can be damaged by systems with a high rise (2 inches or more). Care must be taken, and the designer needs to know what type of vehicular traffic will be driving over the spike system.
Mechanical Systems: Surface and flush mount systems rely on springs or a weighted component to keep the traffic spike in the proper orientation (up) and to allow for automatic retraction when a vehicle passes over the spike in the correct direction. Since these types of systems are 100% mechanical and operate without power, they are sometimes called stand-alone systems.
Motorized (Automated) Systems: Motorized spike systems are driven in the up and down direction by a motorized means. Vehicles cannot simply drive over the spikes and expect the spike to rotate to a passive (down) mode.
The spikes are locked in the up position and must be driven to the down position by a motor to allow traffic to proceed. Motorized systems are typically used with barrier gate operators so that a physical barrier (the arm) is presented to a motorist when it is unsafe (spikes are up) to proceed.
The rotation of the spikes is synchronized with the movement of the barrier arm: barrier arm down – spikes up; barrier arm up – spikes down. The motorized component can be a separate electric drive system to the side of the spike system, or the spikes can be mechanically linked to the barrier gate operator. In either case, motorized spike systems are available with both surface and flush mount spikes.
Unlike stand-alone systems, motorized spike systems often have a maximum lane width that they can be used on. This maximum width varies by manufacturer, so it is essential that the system designer know the lane width and the limitations of the motorized spike system that is specified.
The addition of camera systems monitoring the gate area can also enhance security. These systems are typically connected to a DVR system for recording.
Adding time-date stamping to the recorded video allows the video to be matched with events recorded in the access control or gate operator transaction histories.
This can be helpful, for example, when a gate hits a vehicle. Reviewing the recordings often shows that the vehicle hit the gate!
In more advanced applications, the access control system may be capable of inserting the access granted or denied information into the video, and even adding a picture of the person to match what is being shown on the video.
The sallyport-trap system is commonly used in prisons or other high security applications. In a sallyport-trap, there are two gate systems on a common roadway, providing two points of access control. It is becoming more common to see the use of both conventional gate systems and crash rated active barrier systems performing a sally port action.
Through an electrical interlock or advanced system integration such as a programmable logic controller (PLC), both gates are prevented from being open at the same time. This maintains security while allowing vehicle access.
The time it takes to gain entry or exit is longer, but those facilities requiring a heightened level of security are trading off convenience and speed for added security. This type of system can be designed with any combination of gate types and operators working in unison.
Often vehicle inspections are carried out in this area. The vehicle must pass through the first gate, wait until the first gate is fully closed, then the second gate can be opened for final access to the facility.
Entry Control Point
(ECP) facilities ensure the proper level of access control for all personnel,
visitors, and commercial traffic to a facility.
The goal of an ECP is to secure the facility from unauthorized access and intercept contraband (weapons, explosives, drugs, classified material, etc.) while maximizing vehicular traffic flow.
Planning for vehicle breakdowns and common delays is necessary for both security and avoiding a bottleneck in vehicle flow. Bottlenecks not only slow down vehicle flow but pose a security threat as well.
Design considerations, in order of priority, are:
1. Security
2. Safety
3. Capacity
4.
In some cases, specifications may call for a master override which alters the PLC processing or electrical interlock and allows both gates to operate independent of the other.
Granting access to an extra-long vehicle,
or if one unit is down for maintenance, are just two examples of a desired override.
Vehicle barriers, also known as crash-rated or anti-ram barriers were originally conceived as an anti-terrorist device to protect government installations from vehicles carrying bombs. In 1985 the Department of State (DOS) established standards to address the spectrum of possible incident conditions. These are:
·
Address threat
vehicle types for the location.
·
Define attack
velocities of the different vehicles.
·
Define acceptable penetration limitations.
There are different evaluation criteria for different
agencies that fulfill their unique access
control operations, aesthetics, and other organizational requirements.
In 2007, ASTM first published Test Method F2656 for Vehicle Crash Testing of
Perimeter Barriers. It now is the prevailing standard by which systems are
tested and measured. It was published in 2014.
After 9/11, the Department of Homeland Security has established guidelines for securing critical infrastructure and key assets. These include:
·
Nuclear plants
·
Chemical facilities
·
Public utility
sites
·
Data processing facilities.
One of the means of protecting these assets is the use of vehicle barriers to secure the perimeter from potential terrorist attack. The types of vehicle barriers include:
·
Wedge type road blockers
·
Drop arm barriers
·
Rising bollards
·
Rising beam barriers
·
Net barriers
·
Reinforced slide and swing gates.
The rating and testing of these barriers can be found in ASTM F2656 and establishes several levels of crash resistance, penetration and disabling of the vehicle.
The following chart shows the two most often specified levels of crash rating in both systems, ASTM F2656 versus Dept of Transportation ratings:
|
ASTM
F2656 |
DOS Rating |
|
M50 |
K12 |
|
M30 |
K4 |
In the ASTM system, ‘M’ refers to a 15,000lb medium duty truck. ‘50’ refers to the speed at which
the crash test took place, 50mph.
In addition, there are modifiers for the distance the truck bed penetrated the barrier – P1, P2, and P3. P1 is the least penetration, which may be important in maintaining standoff distance.
|
Penetration Ratings |
|
|
Designation |
Dynamic Penetration Rating |
|
P1 |
≤1 m (3.3
ft.) |
|
P2 |
1.01 to 7 m (3.31 to 23.0 ft.) |
|
P3 |
7.01 to 30 m (23.1 to 98.4 ft.) |
Wedge type barriers, arm barriers, bollards, and rising beam barriers are powered either by hydraulic cylinders driven from a hydraulic pump system, or electromechanical systems driven by electric motors and high-powered electronic servo drives.
Wedge barriers, bollards, and rising beam barriers often contain hydraulic accumulators that allow the devices to be deployed very rapidly, sometimes as fast as 1.5 seconds, in response to an imminent threat.
Take care to evaluate the threat and the rating of the system needed, but emphasis must be placed on the cyclic demand of the system. Some active barrier systems may only be asked to operate in an emergency while others may cycle hundreds of times throughout the day.
The design of the
system as it applies to the duty-cycle is not standardized and consulting the
manufacturer and product
data sheets is important. Since these barriers
are designed to be very formidable and the intent is to
thwart entry, there exists the risk that an oblivious, yet innocent, driver
could contact a barrier.
The most effective means of mitigating this risk is with traffic calming measures. Creative landscaping, turns, speed bumps, or other methods of reducing approach speed are available.
Lighting on the barrier and appropriately conspicuous striping is encouraged to draw attention to its presence, as well as warning signs. Net type barriers have been developed to reduce the potential of death or injury during stoppage of a vehicle, but penetration by the vehicle can be greater on these barriers.
In addition to anti-terrorist barriers, there are also a class of lower rated barriers that are used mostly for discouraging malicious behavior at access control points. These include small surface mount plate barriers, smaller bollards, and tiger teeth.
These types of
barriers can be found in rental car facilities, automobile dealerships, valet
lots, etc., where the purpose is to keep the cars in, rather than keeping
intruders out.
·
Explore the key requirements for different projects, including building
codes, safety codes, historical standards, and neighborhood rules.
·
Learn the importance of planning for underground utilities, driveway requirements,
power sources, and emergency access.
·
Know how to choose the right gate operator based on project needs,
integrate with vehicle detection and safety systems, and ensure proper security
and safety training.
·
Create and finalize comprehensive designs, use checklists and
documentation, and apply best practices for testing, inspections, and customer
approval, while tailoring designs to specific projects.
The factors that are needed in designing an automated gate system have been covered. This provides the background information for most generic system designs. Now we must take this information and match it to what may be required for each project. This chapter is intended to help tie this information together when approaching an automated gate system design project.
Before putting all the pieces together for a project, are there any special requirements for this type project. These include:
· State/local building codes
· Life safety or fire codes
· Historical preservation standards
· Neighborhood covenants.
This will require some research on the part of the designer and may involve contacting different sources to determine if there are any requirements that will apply to the project site. Some things to consider may include:
· “Call 811 Before You Dig”. This may affect underground footings, and conduit runs.
· The minimum size of the opening and/or driveway. And does this apply to one gate or all gates?
· Historical or HOA covenants for design considerations regarding style, size, or colors?
· How far must the gate be from the public right-of-way?
· How far must the telephone entry or access control devices be from the public right-of- way?
· Is a turnaround required to prevent denied access vehicles from backing out into traffic? If so, is there a specific turning radius or size specified for the turn around?
· Are specific state/local licenses required by the installation company?
· Which project contractors are required to pull permits and if so, where can they be applied for and how much do they cost?
· What type of emergency responder access equipment is required?
· Is emergency responder access required on each site gate or is only a designated gate(s) required to have the overrides?
· Are there other fire code requirements (power back up, open upon power fail, etc.)?
· Does the fire marshal’s office require a permit be pulled with them and if so, what is the cost?
· Is an annual inspection by the fire marshal’s office required once the project is completed
· and if so, is there a cost for the inspection?
· Is special signage required by local code and if so, what are the specifics?
· Is there a timeline for site inspections by code/fire officials?
· Is there a plan review or municipal committee that must first okay the project?
Be specific and clear when describing the project. It is important to get the right information at the start. Get written documentation or print the requirements out from a website and place these in the project file for future reference.
The design process will vary based upon the type and scope of the project. In most cases, an initial meeting with the customer will be needed to get an idea of what the customer’s expectations are for a gate system…expectations, not needs.
To properly address the customers’ expectations, it is best to find out why the customer feels that they want a gate system installed. Often, an event has occurred on site, or in the area, that has prompted the desire to install an automatic gate system, especially if it is an existing site.
The reasons people add a gate system to their property can vary significantly and is sometimes difficult to define. It may take some investigation, and clear conversations with the customer to fill in these blanks. These are just a few of the questions to be asked of the customer:
· What do they hope to get from the finished system?
· Remember “expectations” are different from “needs”.
· Did some events occur that caused them to put in a gate system?
· Are kids playing and kicking a ball into the street?
· Are dogs terrorizing the neighborhood?
· Are they trying to improve the aesthetic value of the property?
· Did a neighboring property add a gate, and they want to keep up?
· Are they addressing a security issue?
· Is this the contractor, installing an economical gate just to meet the property requirements for a gate? (If so, allow for future expansion of the system once the property owner takes over).
Determining what the customers “expectations” are for the system will help identify what is needed in the system. And finding out what the specific needs are in the beginning will help ensure that all project considerations are addressed.
After determining the customer’s expectations and needs, it is time to contact the local code
authorities and determine the requirements of each code
entity.
Create a checklist to use when talking with the customer that can be used when walking the job site. This should include the following type of questions/information: (Some of these questions are related more to commercial/industrial locations than residential)
· What is the UL 325 Class of installation is the job site?
· Which type of gate will work best, swing, slide, vertical pivot, vertical lift?
· Is this a single or double (biparting) gate?
· Other than ASTM F2200, what design criteria does the gate panel have?
· Where is pedestrian access/egress located?
· Is additional fence, brickwork, asphalt work, landscaper, etc. needed?
· Where is the DOT right-of-way from the center line of the road?
· Be sure to check grade conditions.
· Is there backspace for slide gates?
· Is the swing gate path clear of obstructions?
· If there is an island, is it wide enough for the operator and support posts?
· Is there common area available or will the equipment be mounted on private property?
· Are there landscaping issues that affect the gate system or path of the gate:
· Planters,
· Shrubs,
· Retainer walls,
· Mulched beds etc.
· Sidewalks or walking paths?
· What is the driveway surface?
· Dirt or gravel
· Builder layer asphalt or finished asphalt road
· Concrete, stamped concrete, colored concrete
· Is the road new or existing?
· Will additional lighting be required for the new gate area?
· Where is the power source? Is there an existing meter close to the gate area or will new services have to be installed?
· Who is supplying the gate, and will it meet ASTM F2200?
· If the physical gate/s pre-exists, can it be brought into ATSM F-2200 compliance?
· Are the pre-existing gate’s support posts, track, rollers, hinges etc. capable of handling full
· automation and the new operational requirements?
· Does the new operator match the appropriate type gate, class of install and general site requirements?
· Does the system require power fail options?
· Are gate locks required?
· What type of vehicle detection system will be required and how will it be installed on the site?
· What forms of entrapment detection will be used on site?
· Will a maintenance contract or specialized training be required?
· Are there site-specific security requirements for the project?
· Will the project require site specific safety training (OSHA 10 or 30, on site safety training, pre-construction, weekly progress meetings, etc.…) or personal protection equipment?
· Will there be an equipment testing period for customer acceptance requirements prior to finalization of the project?
· Are there any site hazards or EPA concerns for the project?
· Is there any independent testing, as-builts or manufacturer certificates of compliance required for customer approval to finalize the project?
· Will the project require certified payrolls, prevailing wage rates or union influence?
· Are there any hazardous site conditions, explosion potential, underground obstructions, etc.?
· Will the site require a Sallyport/Trap operation to meet security requirements?
These are just some of the information that may be needed to be included in the system design. Some projects will require less information while some may require more.
Develop a checklist that can be used companywide and reference equipment that it is most often used within the company. Here are a couple examples of site checklists.
See the following
two pages.
Drawing 46-6020
Drawing 46-6021
It is important to select the correct gate operator for the project. There are several factors that should be considered:
· Size and weight of the gate.
· Electrical power available
· Duty cycle of the gate (how many people will use this during peak activity).
To determine the number of times a gate system will operate, it is important to look at the type of property, and how people will use the gate. Asking the customer, “How many times will the gate open per day” is not how to get an accurate estimate. The more important issue to know is the number of gate cycles per hour during the peak of activity.
For Class 1 and 2 installs
· Count the number of houses or apartments the gate/s will serve.
· Multiply this X 2.5 to determine the number of vehicles behind the gate.
· This provides an indication on how many people may pass through the gate between 6- 8AM as the tenants leave for work.
· This is the peak number of cycles for the gate.
For Class 3 and
4 installs:
· Count the number of storage units, bay doors and parking spaces.
· This would be the minimum usage number to start with.
· Are there 2 shifts that overlap?
·
This will give an idea on the peak gate cycle.
· What type of vehicles will use the system?
· Passenger vehicles
· Delivery trucks
· Semi-tractor trailer - big rigs
· Motorcycles
· School buses, etc.?
· Who will use the gate?
· Residents
· Visitors
· Vendors, deliveries, paper carriers, postal service, utility company, garbage service
· Emergency responders. etc...
· What type of access device will be used by each group? Cards, codes, transmitters?
· What type of pedestal or mounting may be required for the access devices?
· Will a transaction record system of use be required and if so, for valid, denied, entry only or both entry and exit or any combination of actions?
· Will the pedestrian access/egress gate be tied to the access control system? Or will it be a standalone access control unit with lock or have a regular doorknob with key lock?
· Is visitor access required?
· Where will the telephone entry/visitor access device pedestal be located?
· Is phone service near the gate?
· Will the job require internet service and if so, where will it come from?
· What are the design criteria for the pedestal?
· If a turnaround is required, how will this affect the placement of the access system.
· Are protection bollards, traffic speed controls, parking blocks, etc. required/desired?
· Who will be programming the system and from where will the system be programmed?
· Will the system be monitored by security either offsite or on site?
· Will remote site access be required by security or guard service?
As with the layout
questions, these are just some of the items that should be answered, and again,
some projects will require less information while some may require more. The more
information that can be defined, the better the system design will meet the
customer’s expectations.
The job of the system designer does not stop at specifying the equipment or simply laying out the job site. As the professional on the project, the system designer also needs to specify or interact with other professionals that may be part of the overall project. The customer is depending on the system designer’s expertise on the project!
The system designer should determine what other professions may need to be part of the spec or bid process:
· Only licensed contractors for the scope of work should be considered to bid the project.
· Is a certification required for the gate system installer? If so, this person should be required to perform and oversee the work.
· Contractors should present Certificates of Insurance and Workers Comp coverage with their bid.
· Contractors should provide a comprehensive warranty statement covering materials and labor with their bid.
· Contractors should be responsible for all required permits, fees, and licenses for the project.
· Contractors should be required to meet with the customer or customer’s representative to
· go over the finalized work.
· Contractors should provide training on the operation and maintenance requirements of the system.
Additional
points can certainly
be added based on customers’ requirements.
Remember UL 325 and ASTM F2200. Gate operators should be installed only when the following conditions have been met:
· The gate operator is appropriate for the construction of the gate (type) and the UL 325 classification of the gate.
· Gates are to be provided with auxiliary supports to prevent a gate from falling over more than 45 degrees from its vertical plane.
· Automated gates must have all gate latches disabled.
· The gate must be balanced so that it does not open or close on its own when disconnected from the operator.
· All openings of a horizontal slide gate are guarded or screened from grade to a minimum of SIX FEET or the top of the gate (if less than 6 feet) to prevent a 2 Ľ inch (57.2 mm) diameter sphere from passing through the openings of the gate.
· The same screening requirements apply to that portion of the adjacent fence that the gate covers in the open position.
· All exposed pinch points are eliminated or guarded.
· There should be no protrusion greater than one-half inch on the bottom or vertical edges of the gate and all protrusions must be smooth.
· Allowable protrusions are top pickets and top decorative designs; gate locks, wheels, and positive stops on horizontal slide gates; bottom retainers in Class IV horizontal slide gates; and positive stops at the top of vertical lift gates.
· Barbed wire cannot be installed at a height lower than six feet, and barbed tape cannot be installed a height lower than eight feet.
· Guarding is supplied for exposed rollers.
· Pedestrians must be supplied with a separate access opening. The pedestrian access opening shall be designed to promote pedestrian usage. Locate the gate such that persons will not encounter the vehicular gate during the entire path of travel of the vehicular gate.
· The gate must be installed in a location so that enough clearance is supplied between the gate and adjacent structures when opening and closing to reduce the risk of entrapment.
· Swinging gates shall not open into public access areas.
· The gate must be installed properly and work freely in both directions prior to the installation of the gate operator. Do not overtighten the operator clutch or pressure relief valve to compensate for a damaged gate.
· The minimum distance between all access controls and the gate and operator is six feet.
· A minimum of two approved warning signs/placards must be installed in the vicinity of the gate and must be visible to persons approaching the gate from either direction.
In closing, take pride in all the work being done. Be a part of a profession that affects people from all walks of life. It is easy to throw together a list of equipment that will move a gate back and forth across a roadway opening. However, designing a system that provides the desired functions & operation, have an aesthetically pleasing appearance, can perform reliably under the workload of the application, and meets the expectations and needs of the property owner is a lengthy process.
Take time to do the research. Find all the factors that may apply. Use all available resources. Work with known distributors and suppliers. Talk with the manufacturer’s representatives, use the online resources that the AFA provides. Then, work with the customer to develop a system that best meets all the standards, requirements, expectations, and needs.
The following are some additional layout check list examples for
reference.
Drawing 170-2410
Drawing 188-2411
Drawing 187-2412
We are including some typical system layout examples showing different types of gates, and notations for the system equipment and operation. Take some time to review these and consider how these may relate to project you have worked with or may work with in the future.
Remember,
there is no “One” layout that will work with every application. Each project is unique and
has its own set of requirements. These are just examples showing
some layout ideas.
Drawing 185-6023
Drawing 184-6024
Note: Manufacturers may use different terminology to describe the same or similar functions.
Access code (additional terms: Entry Code, Keyless Entry, Pin number) A code entered at the main system keypad to activate the system relay.
Access code (additional terms: Master Code, Password, and Programming Code) A security password required to begin programming sequence for a telephone entry system.
Access level (additional terms: Security Level, User Group) A pre-defined set of rules used to grant, restrict, or prevent access when assigned to personnel. An access level is a combination of doors/gates and time zones (ex. card authorized for door 1 Mon-Fri, 8AM – 6PM).
Anti-pass
back - A feature that restricts the user passing
through a defined Entry point into a
controlled area. There are 2 versions of this feature: Timed Anti-Pass back and
True Anti-Pass back:
· Timed Anti-Pass back does not allow reentry for x amount of time (programmable)
· True Anti-Pass back never allows reentry until the user exits the property. There is a variation of this. The system may reset at a specified time and allows entry the following day.
Auto Lock / Unlock schedule (additional terms: Relay Hold, Door Lock/Unlock) Pre-programmed time zones for gates / doors at a property to be locked or unlocked. In gate operator applications this would hold the gate open during designated time zone.
Barium ferrite reader – This is a type of card reader, also known as a touch plate reader, because the card must be placed correctly against a metal plate.
Baud rate - Speed of data transmission from a computer to a TES unit, or between multiple controllers that are connected.
BBU, Battery back-up - May provide operation of the TES unit when primary power fails. In some brands, this may be required to back up the system memory when power fails.
Biometric reader - Type of card reader that uses some part of the human body for identification purposes (fingerprint, retinal scan, thermal face scan, etc.)
Butt set (additional terms: Test Phone) - Also telephone lineman’s butt set. This is a tool used
to connect to an existing phone line to test that line’s operation.
Card code (additional terms: Device Code, Access Code) - A 5-digit card number that is programmed into memory to grant access. The term Card Code is often used as a generic term for other access devices.
Dedicated phone-line system (additional terms: Auto Dialer) - A telephone entry system which requires that a phone line be connected to the unit. The entry system places a phone call to the tenant and communication is established.
Demarcation point – The location in a home or building where the local telephone company terminates their phone lines and ceases to accept responsibility for line maintenance. In a single residence, this point is usually on the outside of the building. In a commercial property or multi- family dwelling, it is usually in a room or area not accessible by the public.
Directory code - Code in telephone entry system that is assigned to a specific phone number. May also be associated with name and access device codes. The directory code is entered at the system keypad to initiate a phone call to the tenant.
Door strike - Locking device for door. Requires power to unlock the door. Different models can be either continuous duty or temporary duty. Door strikes may be Fail-Safe or Fail-Secure.
DSL (digital subscriber line) - Phone line carries both analog signal and digital component for high-speed internet access. In some brands, this digital component must be split off before connecting to a TES unit or it can cause problems in operation and damage to circuit boards.
DTMF - Dual-Tone Multi-Frequency, or DTMF, is a method for instructing a telephone switching system of the telephone number to be dialed, or to issue commands to switching systems or related telephony equipment. DTMF is a telephone company term for the tones that you hear when you press the numbers on a touch-tone telephone. The version of DTMF used for telephone tone dialing is known by the trademarked term Touch-Tone.
Duplex Communications - A duplex communication system is a system composed of two connected parties or devices which can communicate with one another in both directions. Telephone entry systems on the market today can be either full-duplex or half-duplex. Look closely at the manufacturer’s specifications to determine what type of duplex system is used on any model of a telephone entry system.
A half-duplex system provides for communication in both directions, but only one direction at a time (not simultaneously). Once a party begins receiving a signal, it must wait for the party to stop transmitting, before replying. An example of a half-duplex system is a two-party system such as a walkie-talkie style two-way radio, where the user must use “over” or another previously designated command to indicate the end of transmission and ensure that only one party transmits at a time because both parties transmit on the same frequency.
A full-duplex system allows communication in both directions, and unlike half-duplex, allows this to happen simultaneously. Land-line telephone networks are full-duplex since they allow both callers to speak and be heard at the same time.
Earth ground - A neutral electrical point under the earth. NEC code stipulates a minimum 8-foot depth. By installing a metal rod into the earth, a connection can be made to this ground point. When this is not feasible, an acceptable earth ground can be a cold-water pipe or electrical panel if it is within 12 feet of the system.
Entry code (additional terms: Access Code, Keyless Entry, and PIN Number) - Keypad code used for tenant entry.
Facility code - 3-digit code specific to an overall installation which increases the available number of cards that can be issued before any repetition of card #s occurs.
Isolation relay - An external relay used to isolate the circuit board from a potentially noisy strike, high voltage, or another device.
Latch relay – Changes the relay
state for an indefinite amount of time.
LCD - Liquid crystal display
used to display
tenant names and directory codes
on a TES unit.
LED display - Light emitting diode display.
Mag-lock - Magnetic door lock that requires power to stay locked. This may require a reverse bias diode to be used across the power supply to protect the entry system from spikes generated by the lock.
Modem (additional terms: Voice Modem, Dial Up Modem) - Device that converts data into sound for transmission over telephone lines. Used for programming the connection between a telephone entry system and a programming computer.
Modem initialization string - Initialization string for a telephone modem
MOV - Metal oxide varistor, used to help protect a circuit board from noise and voltage spikes that could interfere with operation.
Multi Conductor Cable - Multiple wires inside an overall jacket. Commonly found in 2 cond., 4 cond., 6 cond., 8 cond., etc. Each wire has an individual color: Red, Black, White, Green, Brown, Blue, Orange, etc.
Multi
Pair Cable - Multiple pairs of wires inside an
overall jacket. Pairs may be color matched (i.e.,
Blue White/White Blue, Green White/White Green) or may be solid colors (Red/Black, Blue/Black).
Multiple Entry - More than one system sharing
a phone line.
No phone-bill system (additional terms: No Phone Line system, Shared Phone line System, Telephone Intercom System) - A telephone entry system that generates its own phone-line voltage and ring signal, so the customer does not have to pay a monthly phone bill. This type of system requires a physical connection to all the phone lines in each property.
Off-Hook - In telephony, the term off-hook
has the following meanings:
1. The condition that exists when a telephone or other user instrument is in use, i.e., during dialing or communicating. Note: Telephone handset is not resting in cradle or is turned on. Hands free is turned on. Dial tone can be heard from handset or hands free.
2. One of two possible signaling states, such as tone or no tone and ground connection versus battery connection. Note that if off-hook pertains to one state, on-hook pertains to the other.
3. The active state, i.e., a closed loop of a subscriber line or PBX user loop.
On-Hook - An operating state of a communications link in which data transmission is enabled. In telephony, the term on-hook has the following meanings:
1. The condition that exists when a telephone or other user instrument is not in use, i.e., when idle waiting for a call. Note: Telephone handset is resting in cradle or is turned off. Hands free is turned off.
2. One of two possible signaling states, such as tone or no tone, or ground connection versus battery connection. Note: if on-hook pertains to one state, off-hook pertains to the other.
3. The idle state, i.e., an open loop of a subscriber line or PBX user loop.
PBX Digit - A Private Branch Exchange (PBX) is an internal phone system that connects to phones within the system using extension numbers rather than independent phone numbers. When dialing to a number outside of the system an initial digit (usually a 9) must be dialed to access an outside line. In some TES units a PBX digit may be assigned. When programmed telephone numbers are less than 7 digits in length, the system will dial only those digits. For programmed numbers of 7 digits or more, the system will dial the PBX digit followed by a 1 second pause before dialing the programmed number.
Postal lock input - An input on the TES board that can be connected to a key / lock structure provided by the post office to simplify access to a property for mail carriers. When the postal lock input is triggered, the TES Relay will activate for the programmed strike time.
POTS Line, Plain Old Telephone Service - Plain old telephone service (POTS) is the voice- grade telephone service that remains the basic form of residential and small business service connection to the telephone network in most parts of the world. This provides Tip and Ring voltage for an analog telephone communication signal. The name reflects the telephone service still available after the advent of more advanced forms of telephony such as ISDN1, mobile phones and VoIP.
Proximity reader - Type of card reader that allows a card to be presented in general proximity to the reader. Depending upon the model purchased, the range at which the card can be read is between 3 inches and 24 inches.
Release relay - Clears latch command and
returns relay to normal state.
RF Receiver - RF (Radio Frequency) type reader that supplies a Weigand output to the controller.
Ring equivalence - The amount of current required to ring a phone as compared to a standard bell telephone. Most phones will have this number listed on the bottom of the phone.
Ring polarity – Older phones were polarity sensitive. If the TIP and Ring (Green and Red) wires were not correctly connected, the phone would not ring. Most current phones do not have this problem, so it is not necessary to consider polarity when connecting a phone line.
Ring Voltage - To ring the telephone, a 90 VAC signal is superimposed over the DC telephone signal. This will Ring the bell or sounding device inside the telephone. Note: On some newer telephone technologies, this voltage may be less than 90 VAC, and may be as low as 50 VAC.
RS-232 port (additional terms: Serial Port) - Standard I/O port for a computer data from external devices (printers, modems, palm pilots, etc.) are transmitted and received through this port. The distance limitation for this format is about 50 feet. Many PC’s today require a USB to serial adaptor for connection to this type of device.
RS-422
port - Alternate format for data exchange which has an effective distance of about 1000 feet.
RS-485 port - Alternate format for data exchange which has an effective distance of about 4000 feet. This format may also be used for connections to remote card access devices.
Shielded cable - Group of wires with a metal encasement underneath a non-conductive, weather- resistant insulation (usually plastic). The metal shield is tied to an earth ground at one end to limit external noise interference.
Swipe reader
- Type of card reader where card must be swiped
through a channel
in the reader.
Time zone - Restricted days / hours for entry (ex. Monday - Friday 8 AM - 5 PM).
TIP and RING - The 2 sides of a telephone line needed for hook-up to a TES. A standard telephone line will read 48 – 52 VDC (Volts Direct Current) between these 2 points when the phone is not in use, 5-10 VDC when in use.
Twisted-pair wire - Used for audio and data communications to eliminate hum and other noise. The most common for TES applications is Cat5E (category 5E), which has 4-5 twists per inch. Cat3 (category 3), which has fewer twists, is sometimes used by dealers due to lower cost but noise or hum may result in audio communications.
VoIP (Voice over Internet Protocol) - A method for providing telephone service through the internet. The advantage for the customer is a charged a flat rate including all long-distance calls.
Weigand output - Standard format for card data transmission. The industry standard sends data in an SIA 26-bit format. This consists of a Common wire, a data 1 and a data 0 connection. Card or access codes are converted into a combination of data 1 and data 0 pulses. Additional bit formats are available, including: 30-Bit, 31-Bit, 46-Bit and various other formats.
Hopefully, the information in this study guide has given you a new appreciation for what it takes to be a Certified Automated Gate System Designer. Remember, that technology is always changing and with it so must you. To be a true professional you must constantly be expanding your knowledge and apply it in a way that promotes your industry to the consumer in a positive and meaningful way.
This is just the beginning
of a lifelong commitment to being a true industry
Professional.
For more information and updates on UL 325, and other important industry developments to be addressed throughout this study guide, the following organizations can be used as sources.
1)
AFA - American Fence Association
Phone: (800) 822-4342
6404 International Parkway, Suite 2048-A
Plano, TX 75093
2)
NOMMA - National Ornamental & Metal Manufacturer’s Association
Phone: (888) 516-8585
1535 Pennsylvania Ave
McDonough, GA 30253
3)
DASMA – Door &
Access Systems Manufacturer’s Association
Phone: (216) 241-7333
1300 Summer
Ave
Cleveland, OH 44115-2851
4)
UL – Underwriters Laboratories
Phone: (847) 664-2023
333 Pfingsten
Road
Northbrook, IL 60062
5)
ASTM – American Society of Testing
and Materials
Phone: (610) 832-9500
P.O. Box
C700
West Conshocken, PA 19428-2959
6)
NEMA – National Electrical Manufacturers Association
2101 L Street Northwest, Washington, DC 20037
7)
IDEA – Institute of Door Dealer
Education and Accreditation
Phone: (937) 698-1027
Post Office
Box 236, West Milton, OH 45383
8)
IDA – International Door Association
Phone (800) 355-4432
Post Office Box 246, West Milton,
OH 45383
Electrical definitions from the Tech Encyclopedia off the Tech Web.
www.answers.com/topic/alternating-current
Wikipedia, the
free encyclopedia.
Technical support provided by Peek Traffic, Reno A&E, BD Loops, and Preferred Technologies
Group in the preparation of this section. With their permission, entire excerpts have been taken from their manuals, and they have reviewed this self-study guide.
Although the stated purpose of industry sponsored training is never to endorse a specific manufacturer over any other, the level of technical information required about vehicle detectors mandates a credible technical source which only a manufacturer can provide. Whatever brand of vehicle detector your company uses, be certain to obtain and study the equivalent technical information from that manufacturer.
MODOT.org
1. International Building Code (IBC) – 2009 edition and later
2. International Fire Code (IFC) – 2009 edition and later
3. International Residential Code (IRC) – 2012 edition and later
· ASTM F900 - Industrial/Commercial Swing Gates
· ASTM F1184 - Industrial/Commercial Horizontal Slide Gates
· ASTM F1911 - Installation of Barbed Tape